日本応用磁気学会誌
Online ISSN : 1880-4004
Print ISSN : 0285-0192
ISSN-L : 0285-0192
10 巻 , 2 号
選択された号の論文の80件中1~50を表示しています
磁気記録媒体
  • 高橋 隆一, 宮田 努, 吉田 順作
    1986 年 10 巻 2 号 p. 51-54
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    This paper is concerned with the experimental results of the high rate and low temperature deposition of Co-Cr films using an exposed pole (EP) magnetron co-sputtering system developed by the authors for deposition of ferromagnetic binary alloy films. In this paper we prepare a composite target constructed of a Co washer, a Cr cylinder and a Co disk, and examine the performance of the sputtering system and evaluate the film quality.
    Results :
    1) Maximum deposition rate was as high as 0.18 μm/min for 7.6 W/cm2 input power.
    2) The deposition rate was higher for lower sputtered gas pressure.
    3) The substrate temperature was as low as 100°C for 7.6 W/cm2 input power.
    4) The C-axis of the deposited Co-Cr films were in the perpendicular direction to the film plane and Δθ50=8-13°.
    5) Perpendicular magnetic anisotropy films were obtained for the films of Ms=300-800 emu/cc and Hc=250-350 Oe.
    Thus, it is concluded that EP magnetron co-sputtering is very effective for the deposition of Co-Cr films.
  • 河内山 彰, 坂井 郁夫, 住田 勲勇, 中山 靖彦, 浅沼 満
    1986 年 10 巻 2 号 p. 55-60
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    CoCr thin films having a thickness from 0.014 μm to 0.5 μm were prepared by D.C. magnetron sputtering method using CoCr (18 wt% Cr) alloy target on PET film.
    Thicker films are characterized on three zones which have different magnetic properties. In the first zone, films up to 0.03 μm thickness have very low coercive force Hc and small saturation magnetization Ms, and a poor vertical anisotropy. In the second zone from about 0.03 μm to 0.1 μm, Hc and Ms vary passing along the maximum value, but in this zone anisotropy field Hk is smaller than that of the third zone. In the third zone Hc gradually decreases with increasing film thickness, while Ms approaches a constant value and Ms reaches the highest constant value. TEM studies show CoCr films to have a fine columnar structure in thickness greater than 0.03 μm, and no changes in structure or diameter of the column have been observed in the 2 nd and 3 rd zones.
    To investigate the effects of the underlayer, various kinds of metal were deposited on the PET film prior to CoCr deposition. Double layered CoCr films exhibit higher Hc than single layer and have poor crystalline orientation. SEM observation shows that CoCr films on the metallic underlayer have smaller grain size than do single layered films.
  • 岩崎 俊一, 大内 一弘, 木村 正克, 斎木 幸治
    1986 年 10 巻 2 号 p. 61-64
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    The effects of H2, O2 and N2 additives on the magnetic properties of Co-Cr film were studied for high rate sputtering. O2 and N2 react with Co-Cr to from compounds. N2 addition induces fcc <200> orientation perpendicular to the film plane, and hence causes a drastic decrease of the perpendicular anisotropy field Hk, accompanied by hcp <002> orientation degradation. O2 is most reactive to Co-Cr, but little affects the crystal structure. These effects become less at higher deposition rate for the same introduced pressure. In contrast, H2 does not react with Co-Cr at all, but has a unique role of changing the coercive force without any change of Hk or crystal orientation. The effects of N2 and H2 are concluded respectively equivalent to that of increase and decrease of substrate temperature.
  • 田中 勉, 大内 一弘, 岩崎 俊一
    1986 年 10 巻 2 号 p. 65-68
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    In order to investigate the reversal mechanism of magnetization, angular dependence of hysteresis loss was discussed for Co-Cr perpendicular recording media. For a so-called double layer medium which consists of a Co-Cr layer and a Permalloy back layer, it was easily shown that the Co-Cr layer shows rotational reversal of magnetization. Judging from both angular dependences of Hc and hysteresis loss, the initial and column layers in Co-Cr sputtered film were found to show magnetization reversal by domain wall motion and by rotation, respectively. Other Co-Cr films which have different Ms and Hc were also studied with respect to their reversal mechanism of magnetization.
  • 堤 和彦, 福市 朋弘, 藪下 宏二, 梅崎 光政, 菅原 宏
    1986 年 10 巻 2 号 p. 69-72
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Perpendicular magnetic recording is promising for the achievement of higher recording density. Magnetic and crystal orientational properties of double layer rigid disks for perpendicular magnetic recording were studied. Coercive force distribution of the Mo-Cu-permalloy underlayer was investigated as a function of sputtering gas pressure. At optimum Ar gas pressure, good uniformity of coercive force distribution was obtained. Even in double layer medium, crystal orientation of the Co-Cr layer was influenced by the characteristics and thickness of the substrate surface treatment layer. Higher recording density was obtained with lower flying height and a thinner Co-Cr layer. The D50 recording density of 70kFRPI was achieved for a 0.15 μm thick Co-Cr layer and a 0.3 μm thick single pole type head at 0.1 μm flying height.
  • 田万里 耕作, 大越 正敏, 本多 茂男, 楠田 哲三
    1986 年 10 巻 2 号 p. 73-76
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    To clarify the influence of CoO spins on magnetic properties of Co-CoO reactive sputtered films, Co-CoOx compositionally modulated (C.M.) films were investigated. These Co-CoOx C.M. films were prepared with modulating oxygen partial pressure in a chamber (Po2). These films have Co-CoO interfaces parallel to the film plane. Coercivity (Hc) and in-plane anisotropy (K//) of C.M. films with short modulating periods increase remarkably below Néel temperature of CoO (=292K). These increases in Hc and K// at low temperature are thought to originate from the magnetic interaction between Co spins and CoO spins.
  • 逢坂 哲彌, 小岩 一郎, 戸田 雅規, 佐久間 毅, 山崎 陽太郎, 並河 建
    1986 年 10 巻 2 号 p. 77-80
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Electroless Co alloy films tor perpendicular magnetic recording medium were investigated as a function of thickness dependence on magnetic properties. The read/write characteristics, especially the dependence of overwrite on recording density showed a large difference between Co-Ni-Re-Mn-P and Co-Ni-Re-P films. Since those films displayed a different thickness dependence of perpendicular coercivity Hc(⊥) , the control of thickness dependence of Hc(⊥) was attempted for Co-Ni-Re-P alloy films. The thickness dependence of Hc(⊥) of Co-Ni-Re-P alloy films could be easily controlled by adjusting the sodium malonate concentration in the bath. When the film becomes very thin, such as 0.1 μm thick, the Hc(⊥) value and degree of c-axis orientation increased with an increase in sodium malonate concentration, however, when the film thickness increases up to 0.5 μm. those values become almost the same for different sodium malonate concentrations.
  • 深谷 敏雄, 小口 寿彦, 竹内 肇, 日出山 章蔵, 横山 弘毅
    1986 年 10 巻 2 号 p. 81-84
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Stress and temperature stabilities for Ba-ferrite perpendicular magnetic recording media have been investigated. Stress-induced decrease rate in remanent magnetization for the media was found as small (1 × 10-5 per kg/cm2) as those for metal and Co-γFe2O3 media. Remanent magnetization in a perpendicular direction remains almost constant in a −10 to 80°C temperature range. Output decreases after 120 minutes still mode reproducing with 8 mm VCR, and 10 million passes with a 3.5 inch FDD were less than 1 dB. These results confirm the excellent stability of the Ba-ferrite recording media.
  • 千葉 雅史, 小泉 義晴
    1986 年 10 巻 2 号 p. 85-88
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Magnetic thin films of Mn-ferrite (MnFe2O4) have shown a large perpendicular magnetic anisotropy by the evaporation method. The evaporation substances are the (AαBβ)100-xCx system, where A, B and C represent the matrix elements of combination for Mn, Fe and Bi, respectively. For (Mn25Fe75)97Bi3 the pillar-shaped grain, MnFe2O4 deposited onto substrate has an anisotropy constant of 4.4 × 105 erg/cm3, 4πMs 1.6 × 103 gauss and Hs 540 Oe. The configuration and magnetic properties in evaporated film composition are closely related. It was recognized that in order to get magnetic thin films with perpendicular anisotropy it is important to form a first layer of Bi phase with <102> configuration onto substrates.
  • 田中 敏雄, 国分 明男
    1986 年 10 巻 2 号 p. 89-92
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    An observation method where the primary electron beam is parallel to a sample is proposed. The leakage magnetic field emanating from recorded magnetization is observed in the secondary electron image by a scanning electron microscope. The secondary electron image is generated due to the quantity difference of secondary electrons, which depends on whether the electron beam is incident to the sample or not, as a result of the horizontal component of the leakage magnetic field. The secondary electron images for the perpendicular recording and the longitudinal recording are shown. A two micron recording length can be resolved by this method.
磁気ヘッド
  • 秋山 純一, 岩崎 仁志, 谷田部 茂, 千葉 脩
    1986 年 10 巻 2 号 p. 93-96
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    A novel magnetic read-out principle is proposed which can extract a high quality output from a high density recorded signal. The principle utilizes a sharp RF permeability change in a soft magnetic film due to a weak external field. This variation is caused by both magnetization rotation and ferromagnetic resonance.
    A magnetic read-out head has been experimentally made which operates according to the novel principle. The manufactured head was evaluated by sinusoidal signals (0.5-10 MHz) which are saturatedly recorded in a magnetic tape with a ferrite ring head (head gap : 0.3 μm, track width : 100 μm).
    The reproduced 0.5MHz signal level from the head is at least 35.7dB higher than that from the ring head, and the 5 MHz signal is 17.6-22.5 dB robustly detected by the novel head. The carrier-to-noise ratio for a 5 MHz carrier (1 μm wavelength) is 44-47 dB and is insusceptible to Ni-Fe film thickness.
  • 岩崎 俊一, 中村 慶久, 渡辺 功, 山川 清志, 長谷川 博幸
    1986 年 10 巻 2 号 p. 97-100
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Effects of domain structures of main pole films on reproducing sensitivities are investigated for single pole type perpendicular magnetic recording heads. The reproducing sensitivity of the single pole head made of a Co-Zr-Nb single layer becomes unstable and decreases with the increase of the closure domain size when the track width narrows and the anisotropy field Hk decreases. On the contrary, for a narrow track main pole made of Co-Zr-Nb multilayered amorphous film with 50 Å thick SiO2 interlayer, the closure domain cannot be observed clearly. Consequently, the reproducing sensitivity becomes larger than that of the single layer main pole and the reproduced voltage is very stable even for smaller Hk and narrower track.
  • 小林 富夫, 窪田 允, 久村 達雄, 佐藤 平吉, 石田 勉
    1986 年 10 巻 2 号 p. 101-104
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    A tilted sendust sputtered (TSS) ferrite head has been developed for use with high coercivity metal tape in high recording density VTR systems. Because the sendust-ferrite boundary plane is at an angle to the gap plane in the TSS head, the interference peaks in the playback output spectrum caused by the pseudo gap between the sendust and ferrite core are significantly reduced. The improved electro-magnetic characteristics of the head produced from sendust-ferrite composite materials have practical application in the field of magnetic recording technology.
磁気記録特性
  • 山本 節夫, 鈴木 幹夫, 中村 慶久, 岩崎 俊一
    1986 年 10 巻 2 号 p. 105-108
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Write spacing losses in perpendicular magnetic recording have been investigated experimentally for a ring head and a single pole head. In ring head recording, an increase of write spacing causes the change of magnetization mode in the Co-Cr layer from perpendicular to longitudinal. In single pole head recording, the magnetization mode remains perpendicular, even for large write spacing. Furthermore, the reproduced voltage in saturation recording decreases with increased write spacing, since the magnetization transition length is broadened by the decreasing write head field gradient resulting from disappearance of head-to-medium magnetic coupling. Therefore, in perpendicular magnetic recording, a slight reduction of the head-to-medium spacing leads to a remarkable improvement in high density recording characteristics.
  • 中村 慶久, 大谷 毅, 岩崎 俊一
    1986 年 10 巻 2 号 p. 109-112
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Computer simulation of perpendicular magnetic recording has been carried out by applying the modified coherent rotation model (Stoner-Wohlfarth model) to the magnetizing process of a Co-Cr layer. The modification has been made so as to fit the calculated M-H loops in the measured loops for various directions of applied field. Using this model, the M-H loop of a sputtered Co-Cr film can be restored by calculation. The reproduced wave form of an isolated pulse and the bit density response obtained by the simulation using the modified S-W model agree well with measurements.
  • 吉田 和悦, 山下 武夫
    1986 年 10 巻 2 号 p. 113-116
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    The noise properties of magnetic recording media partly depend on the type of media, i.e., magnetic thin film type or particulate type. In magnetic thin film media, such as Co-Ni-P plated disks, the lowest noise level is that of dc-erased noise, and when signals are recorded after dc-erasing the level of the modulation noise increases gradually as the recording wavelength is shortened until it reaches a maximum level at a certain wavelength.
    On the other hand, in particulate media, the noise level is highest for modulation noise, followed in turn by dc-erased noise and ac-erased noise.
    In the analysis described in this paper, the irregular fluctuations in the direction of magnetization and the number of magnetic particles per unit volume have been taken into account, and the results of the analysis make it clear that the relative noise level of the ac-erased, dc-erased and modulation noise depends on these fluctuations.
  • 米田 弘, 沢田 武
    1986 年 10 巻 2 号 p. 117-120
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    The simulation of the spacing between a magnetic head and medium has been done to investigate the spacing characteristics for the head shape on a video floppy. In this simulation, the finite-element method is used to solve Reynold's equation and the equation of motion for the transformation of medium. Both the equations are discretized simultaneously. The following results were obtained by this analysis: 1) This method efficiently obtains a convergent solution despite the non-linearity of these equations. 2) The spacing has a tendency to be constant for the head protrusion. 3) The effect of the groove on the head surface is the same as that of the narrow track width of the head. 4) For actual use, sufficient depth and width of the groove are more than 2 μm and 5 μm, respectively.
磁気バブル
  • 浦井 治雄
    1986 年 10 巻 2 号 p. 121-124
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    A new potential well measurement method, using the bubble run-out phenomena, has been discussed for its application to observe charged wall behavior as well as to measure potential well depth itself. The method is applied to bubbles in ion-implanted propagation patterns on 1 μm bubble garnet films with different magnetostriction constants. Bubble run-out directions are found to be reflected by the strength of stress relaxation induced magnetic anistropies along ion-implantation pattern edges. Charged wall length and its stray field distribution are also estimated by the method. It is concluded that this method is one of the most useful tools for operation error mode analysis in ion-implantion bubble device development.
  • S. シュパイデル, 岩田 聡, 内山 晋
    1986 年 10 巻 2 号 p. 125-128
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Computer simulation of the dynamical behaviour of domain walls in bubble films, e.g., for the development of the different functions of the Bloch line memory, are commonly based on the domain wall model developed by Slonczewski. To investigate the degree of reliability of this wall model, we compared numerical results of the dynamics of an infinitely long straight stripe domain with stripe translation measurements, where drive pulses of the order of 2-10 Oe and 50-200 nsec were applied and the total displacement of the stripe, including overshoot, was measured. Numerical and experimental results for the total displacement agree well for drive fields below the experimentally determined breakdown field. The values obtained for the breakdown field also agree well in most cases; however, the discrepancy increases with increasing film thickness and drive field strength. Another discrepancy is the numerical result of a strong dependence of the stripe velocity on the drive field after breakdown in case of thicker films, which is not seen experimentally. Both discrepancies are thought to be results of implicit limitations of the wall model.
  • 岡田 修, 本田 ひろ子
    1986 年 10 巻 2 号 p. 129-132
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Anisotropy changes caused by He+ or H2+ implantations on (100), (110) and (111) magnetic garnet films have been studied. In (100) films, quite in contrast to (111) films, uniaxial anisotropy field changes were almost the same for He+ and H2+ implantations. In (110) films, orthorhombic anisotropy parameter B for H2+ implantations changed greatly, which is consistent with anisotropy change for (111) films. The change in parameter A for He+ implanted (110) films was in the same order as for H2+ implantations. Magnetocrystalline anisotropy K1 in H2+ implanted films was determined from the angular dependence of (100) inplane resonance fields. The sign of K1 changed to positive by H2+ implantations. It was found that H2+ implantations have a great effect λ111 and K1 but have little influence on λ100.
  • 佐藤 靖之, 浜本 正人, S. シュパイデル, 岩田 聡, 内山 晋
    1986 年 10 巻 2 号 p. 133-136
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    It is found that a large orthorhombic anisotropy is induced in (EuBi)3Fe5O12 garnet films grown on (110) NdGG substrates. The Bi content is controlled by controlling the melt composition and the supercooling temperature. Gyorgy's parameter B=−2(Ku+Kp) increases linearly with the Bi content. The main part of B is found to be growth-induced. Gyorgy's parameter A=KpKu is very small and almost independent of the Bi content. The growth- and stress-induced parts of A are found to be considerably large, but of opposite sign, and to compensate each other nearly completely, although their respective absolute values increase with increasing Bi content.
    Magnetic properties of a (Eu1.8 Bi1.2) Fe5O12 film are obtained as follows: saturation magnetization 4πMs = 1560 Gauss, uniaxial anisotropy Ku = 1.6 × 105erg/cm3, in-plane anisotropy Kp = 1.6 × 105erg/cm3, quality factor Q = 1.7, material length l = 0.06 μm and wall mobility μw = γΔ0/α = 19 ms-1. Such a film might be used as a 0.5 μm bubble material for current access devices.
磁気光学
  • 玉城 孝彦, 金田 英明, 対馬 国郎
    1986 年 10 巻 2 号 p. 137-141
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    A compact optical isolator has been developed for a wavelength of 1.3 μm using Bi-substituted gadolinium iron garnet (Gd3-xBixFe5O12) single crystal as a Faraday rotator. The optical isolator features 0.35dB insertion loss, 34dB backward loss and about 33.6dB isolation ratio at a wavelength of 1.3 μm. The insertion loss and the magneto-optical figure of merit are about 0.025dB and 3,000 deg/dB, respectively, at a wavelength of 1.3 μm in Gd1.8Bi1.2Fe5O12.
    Temperature and the magnetic field dependence of the Faraday rotation and the optical absorption have been measured for the single crystals Gd3-xBixFe5-yAlyO12 grown by an improved flux method in which Bi2O3 is used as a flux.
    The saturation field of the Faraday rotation decreases with an amount of AI-substitution. The magneto-optical figure of merit of Fe3+ absorption region at a wavelength of about 0.9 μm was approximately independent of Al content for y<0.5. The Faraday rotation of Gd3-xBixFe5O12(0.85<x<1.2) changes about 7.5%/50°C as the temperature rises above 25°C.
  • 松田 薫, 鎌田 修, 石塚 訓
    1986 年 10 巻 2 号 p. 143-146
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    We studied the melt composition to obtain pit free and highly Bi-substituted (BiLu)3Fe5O12 crystals by the LPE method. First, we confirmed that B2O3 doping into the melt increases Ko(Bi), and found that the decrease of R4 increase the gradient of growth rate dependence of Keff(Bi)/Ko(Bi). Secondly, we found that a mirror-like surface of the crystal is obtained by Gd2O3 doping into the melt. Using the melt with Gd2O3/Lu2O3≥1, the pits, which conventionally appear in LPE growth of (BiLu)3Fe5O12, were suppressed and pit-free and highly Bi-substituted (BiLuGd)3Fe5O12 crystals obtained.
    We measured the optical properties of 250 μm thick (BiLuGd)3Fe5O12 crystal in order to evaluate its applicablity to an optical isolator for a 1.3 μm wavelength range. A sufficient properties of Faraday rotation θF = −1,800 deg/cm and the extinction ratio −40dB were obtained.
  • 石川 武正, 日比谷 孟俊, 小野 賢悟, 白木 健一
    1986 年 10 巻 2 号 p. 147-150
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Two inch diameter, 300 μm thick (BiGd)3(FeGaAl)5O12 films with a mirror surface were grown on {111} Nd3Ga5O12 substrates by liquid phase epitaxy. The extinction ratio was measured for a 30 × 18 mm2 specimen cut from a two inch diameter wafer. A ratio of 37 ± 3dB was obtained throughout the specimen. Several swirl patterns were observed at the periphery of the grown films. The swirl consists of a pit followed by a shallow groove, and was revealed to be caused by a shallow pit corresponding to the defect of NdGG substrate. Degradation of the extinction ratio was found at the pit of the swirl.
  • 本田 洋一, 日比谷 孟俊, 白木 健一
    1986 年 10 巻 2 号 p. 151-154
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    To improve temperature dependence of the isolation value of magneto-optic Bi-substituted garnet films for use in an optical isolator, temperature dependence of Farady rotation coefficient was measured for (RBi)3Fe5O12(R=Dy, Gd, Yb) and (GdBi)3(FeAlGa)5O12 films in 1.3 and 1.5 μm wavelength bands. Among the Bi-substituted garnet films with various composition examined, Dy2.5Bi0.5Fe5O12 films showed a 2% shift in Faraday rotation from that measured at 25°C and assured isolation of 36 dB in the temperature range of 0-50°C. Isolation of 29 dB is assured, even if incident light wavelength fluctuates due to ambient temperature and manufacturing lot. These values correspond to those of Y3Fe5O12 bulk single crystal. From the viewpoint of material designing, temperature dependence of Faraday rotation for Bisubstituted garnets is improved by employing a solidsolution with the rare-earth garnet which has a positive Faraday rotation with negative temperature coefficient of Faraday rotation at room temperature.
  • 腰塚 直己, 横山 侑子, 安藤 功兒, 奥田 高士
    1986 年 10 巻 2 号 p. 155-160
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Epitaxially grown bismuth-substituted iron garnet films with a composition of Y3-xBixFe5-yMyO12 (M=Ga, Al) have been investigated for Bi-induced changes of the growth-induced birefringence ΔnfG and related properties such as the saturation magnetization Ms, the growth-induced KuG, the Faraday rotation θF and the refractive index nf. The optical properties have been measured by the guided-wave optics technique using a He-Ne 1.15 μm laser. The film birefringence has been determined from the phase mismatch between TE and TM modes obtained from the mode conversion efficiency. KuG, θF and nf depend on the contents of both Bi3+ and nonmagnetic Ga3+ or Al3+, while ΔnfG depends greatly on the content of Bi3+. The Bi concentration dependence of ΔnfG is consistent with the form ΔnfG(x) = ΔnfG(0)(x−x0)(3−x0x) described for the case of KuG. The results suggest that the ΔnfG can be ascribed to the changes of the electronic structure and local symmetry of the neighbouring oxygen and iron ions induced by the preferential ordering of the Bi3+ ions on dodecahedral sites.
  • 金子 正彦, 岡本 勉, 玉田 仁志, 山田 敏郎
    1986 年 10 巻 2 号 p. 161-164
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    LPE garnet films (BiLu)3(FeMgPt)5O12 and (BiLu)3(FeAlMgPt)5O12 have been grown using only Bi2O3 as a flux. Annealing after growth as well as MgO doping in the melt has been found effective to reduce the optical absorption at 0.8 μm caused by Fe2+ in the film.
    Optical absorption of both p-type and n-type conduction films is reduced by annealing in the air at 850°C, which means p-type and n-type films are respectively oxidized and reduced in this condition. Various oxygen pressures and annealing temperatures by which films are oxidized or reduced have been determined for n-type and p-type conduction film.
  • 横山 侑子, 高橋 勉, 腰塚 直己
    1986 年 10 巻 2 号 p. 165-168
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Reducing treatment effects on magneto-optical properties were studied for Ca-doped Bisubstituted iron garnet (BiGdCa)3(FeAlGa)5O12 films grown by the LPE technique. The films were reduced by using a hydrazine solution at 100∼110°C. Faraday rotation and absorption loss of as-grown and reduced films were measured at wavelength λ between 0.5 and 2.0 μm. By reducing treatment, the Faraday rotation remained unchanged, however, the absorption loss decreased for both Ca-free and Ca-doped films. The reduced Ca-doped films had lower absorption loss compared with that of the reduced Ca-free films. The minimum absorption loss reached 220 dB/cm at λ=0.79 μm and 1∼2 dB/cm at λ=1.15 μm. The saturation field was below 200 Oe for all the films.
    An optical isolator for the 0.8 μm region was constructed by using a reduced thick film. The forward loss of the isolator was 3 dB and the backward loss 27 dB at 0.79 μm.
  • 斉藤 敏明, 品川 公成, 対馬 立郎
    1986 年 10 巻 2 号 p. 169-172
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    A large magneto-optical effect near the wavelength of 0.7 μm and 1.5 μm in the ferrites containing tetrahedral Co2+ ions is studied on the basis of the crystal field theory, and the present calculated spectrum essentially reproduces the experimentally observed Faraday rotation curves of the Co2+ ion substituted ferrites. Eigenstates corresponding to the 0.7 μm and 1.5 μm transitions are determined in the framework of the strong crystal field approximation using data of the absorption spectra of the tetrahedral Co2+ ions in the garnets. The strengths of these transitions and the spin-orbit interaction coefficients of the excited states are calculated from the eigenstates. With these parameters, Faraday rotation spectrum is calculated in the wavelength range of 0.5 μm -2.0 μm.
光磁気記録
  • 五味 学, 宇都木 潔, 阿部 正紀
    1986 年 10 巻 2 号 p. 173-178
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Highly Bi-substituted Ga : YIG films have been prepared on glass substrates by rf sputterdeposition and post-annealing. For Bi content over 2.5 ions per formula unit, films crystallized in the garnet phase at a very low temperature of 520°C, which allows the use of glass substrate with low heat resistance. Greater Bi content in the film also yielded an impurity phase at lower temperature. Crystallization of the film occurred through the growth of large grain over 100 μm in size for Bi=2.8. Sputter-deposition in pure Ar relaxed optical and magnetic inhomogeneities at these grain boundaries. These were associated with imperfections introduced into the film during deposition. This highly Bi-substituted garnet film may be a promising material for magneto-optical recording.
  • 島貫 専治, 市原 勝太郎, 安田 修朗, 伊東 克己, 近 桂一郎
    1986 年 10 巻 2 号 p. 179-182
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Magnetic and magneto-optical properties of amorphous TbCo films prepared by two target magnetron Co-sputtering have been investigated. Coercive force (Hc), perpendicular magnetic anisotropy (Ku) and Kerr rotation angle (θk) have been measured as a function of sputtering parameters such as Ar gas pressure (PA), substrate bias voltage (VB), target input current (ITb, ICo) and rotation speed of substrate (Rs). Hc and Ku of amorphous TbCo films change considerably with increasing negative VB from 0 V to −660 V and PA from 2 mTorr to 20 mTorr. The VB dependence of Ku shows minimum (Ku<0) and maximum (Ku>0) values around the VB of −200 V and −400 V, respectively. TbCo films deposited at zero substrate bias voltage (VB=0V) and low Ar gas pressure (PA=2∼5 mTorr) show a positive perpendicular magnetic anisotropy of 3∼4×106erg/cm3 in the range of 13-31 at. % Tb.
  • 縄手 雅彦, 楠田 哲三
    1986 年 10 巻 2 号 p. 183-186
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    YFe sputtered films were investigated to clarify the behavior of Fe-Fe interaction in amorphous RE-Fe matrix. The effect of RE magnetism on magnetic properties of RE-Fe films was also investigated using (Gd, Tb)-YFe sputtered films. Amorphous YFe films indicate the spin-glass like characteristics, that is, their magnetization is hard to saturate even at low temperature because of the non-collinear alignment of the Fe moment. The addition of RE element (=Gd, Tb) to YFe film eliminates the spin-glass like nature and the magnetically ordered state can be observed. The exchange interaction between RE and Fe may play an important role in RE-YFe film.
  • 岡本 研正, 戸上 雄司
    1986 年 10 巻 2 号 p. 187-190
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    The homogeneity of magnetic anisotropy of a GdTbFe magneto-optical disk film prepared by rf-sputtering method was investigated by measurement of the oblique Hall effect. Hall samples were cut from the disk along its radius in a size of 7 mm × 7 mm. The magnetic field H was applied obliquely to each sample, and the dependences of the Hall loop upon the azimuthal angle γ and the inclination angle α of the field H were studied in detail.
    The experimental results showed that the disk film is of an oblique magnetic anisotropy in which the in-plane magnetic easy axes lie radially from the center of the disk. It was also found that the inclination angle of the magnetization measured from the film normal increases continuously from the inner side toward the outer side along the radius of the disk.
  • 庄司 益宏, 永井 愛作, 村山 直廣, 小尾 俶久, 藤森 啓安
    1986 年 10 巻 2 号 p. 191-194
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    PtMnSb Heusler alloy films were prepared by RF magnetron sputtering with mosaic targets. Film with a polar Kerr rotation and Clb-PtMnSb (111) diffraction peak was obtained on room temperature glass substrates. The composition range of these films was 19≤x≤32, 35≤y≤46, 28≤z≤38 for PtxMnySbz(x+y+z =100).
    During DC bias sputtering, Sb and Mn contents were selectively decreased by increasing DC bias voltage. For the film deposited at 400°C on a glass substrate, the polar Kerr rotation was found to be 1.18° at the glass side when an external DC magnetic field 7kOe was applied in a perpendicular direction. A columner structure was seen by SEM and some perpendicular component of magnetization was detected by VSM. But these were not enough to exceed the dimagnetization field.
  • 織田 仁, 小野 武夫, 松島 正明
    1986 年 10 巻 2 号 p. 195-198
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    The process of magnetization reversal in a bit written by light was observed by micro Kerr effect measuring technique. Pulsed laser light (wavelength 830 nm), combined with a synchronized and sinusoidally oscillated bias magnetic field, caused repeated writing and erasing of a bit. By monitoring a cw laser light (633 nm) focused on the bit, the change in Kerr rotation angle due to temperature rise was measured. Samples used were amorphous rare earth-transition metal (RE-TM) thin films (TbFeCo) sputtered on glass substrates. The domain in the spot on TM-rich film tends to include magnetic reversal regions when laser power is irradiated in a zero bias magnetic field. RE-rich film, in contrast, has a stable single domain.
  • 太田 賢司, 村上 善照, 乾 哲也, 高橋 明, 出口 敏久, 加藤 昭七
    1986 年 10 巻 2 号 p. 199-204
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    The relation between groove profile and signal quality was investigated theoretically and experimentally in an magneto-optical (M-O) disk.
    First, static characteristics of M-O disks were measured by micro M-O effect measureing apparatus. Kerr rotation angle (θk), reflectivity (R0) and coercive force in grooves 0.65 to 0.91 μm wide and 15 to 87nm deep were similar to those of the plane surface except for the reduction of R0 by the diffraction effect of the groove.
    Secondly, carrier-to-noise ratio was examined by the M-O disk drive, and was compared with theoretical values. The decrease of groove depth and increase of width gave good signal quality. As a result, a high quality M-O signal of more than 60dB was attained in an M-O disk which had a 15nm depth and 0.8 μm width groove and a quadrilayer structure medium which consisted of AIN. GdTbFe and Al.
  • 池松 峰男, 堀合 直, 見山 友裕, 藤井 壽崇
    1986 年 10 巻 2 号 p. 205-208
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Previously we reported that it is possible to record information by means of magnetic holography (using amorphous TbFe thin films as a hologram medium) onto a spot whose diameter is less than 1 mm and to reconstruct it by using the Faraday effect. However, we had not studied the basic characteristics for information storage in detail, and therefore did not then have a proper way of making good holograms reproducibly. Because reproducibility is the most important characteristic for recording, we studied the recording margin for information storage by magnetic holography. In addition, we discussed the relationship between the power density of two beams (object beam and reference beam) and the domain pattern (hologram). It was confirmed that the domain pattern has a close relation to the beam density, and the recording margin depends on the information pattern. From these results, we can make a good hologram reproducibly.
  • 徳丸 春樹, 野村 龍男
    1986 年 10 巻 2 号 p. 209-212
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    A new type of magnetic head (called a domain-modulation-type optical reproduction head) that uses magneto-optical effect as a reproduction principle is proposed. The trial head consists of a high permeability magnetic film and a magnetic garnet film with a reflex mirror. The high permeability magnetic film works as a magnetic flux guide that transfers the fringing magnetic flux from the recorded bits on the magnetic recording medium to a magnetic garnet film and modulates the width of the magnetic domains enough to be reproduced by the laser beam. Therefore, high resolution reproduction in both track density and bit density is expected.
    To investigate the feasibilty of this head, the trial head was put on recorded magnetic tape and the modulated domains in the magnetic garnet film were obsereved through a polarizing microscope. We found that the change in domain width reached more than 1 μm for a magnetic garnet film having a natural domain width of 2.5 μm. Based on analytical reproduction model, this value was sufficient to achieve a high signal to noise ratio (∼75 dB) in reproducing the recorded bits by a 2 μm laser spot.
  • 前戸 邦也, 伊藤 彰義, 小池 修司, 井上 文雄, 川西 健次
    1986 年 10 巻 2 号 p. 213-216
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Highly Bi substituted DyIG thin films on glass substrates having perpendicular anisotropy for magneto-optic recording have been prepared by a thermal decomposition method. Nitrate solutions were spin-coated on glass substrates and the films were annealed for crystallization ranging from 560 to 660 degree centigrade. The films were identified as single phase polycrystalline garnets from X-ray diffraction. By Dy substitution, uniaxial anisotropy energy (Ku) attained to 8 × 104 erg/cm3. Compositional dependence of saturation magnetostriction constant were measured using the cantilever method. It is clarified from a comparison of the measured and calculated values of anisotropies that the large Ku value of Dy substituted films is originated from the magnetostriction and internal stress. From static writing experiments, written bits about 1.5 μm in diameter were obtained. Faraday rotation coefficient is 3.7deg/μm at wavelength 633 nm when Bi content is 1.55 in a formula unit.
  • 五味 学, 麻生川 稔, 阿部 正紀
    1986 年 10 巻 2 号 p. 217-220
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Garnet films R3-xBixFe5-yMyO12(R=Y, Dy, Gd, M=Ga, Al, x=1.5, 1.0, y=0, 0.4, 0.8, 1.2) have been prepared on glass substrates by the pyrolisis method. When annealed above 640°C the films were polycrystalline with no crystal orientation and no impurity phase. They had smooth surface and optical uniformity except cracks, indicating that the pyrolisis method is useful1 for media formation. The magnetization and Faraday rotation of these films exhibited the behaviors expected for Ga or Al substitutions (y) because of the film composition precisely controlled through adjusting the solution composition. The magnetic easy axis in Bi, Ga (or Al) : YIG and Bi, Ga: GdIG films became normal to the film plane for y over 0.8 and just exceeding 0.1, respectively. On the other hand, that of Bi, Ga : DyIG film was normal to the film plane even for non-Ga substitution. This perpendicular magnetic anisotropy was explained in terms of induced stress. These indicate that Bi, Ga : DyIG film is promising material for magneto-optical recording.
ソフト材料・ハード材料
  • 高橋 研, 新井 英雄, 田中 寿郎, 脇山 徳雄
    1986 年 10 巻 2 号 p. 221-224
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    The magnetocrystalline anisotropy constants, K1, of the Sendust alloys (7∼11 wt% Si, 4∼7 wt% Al, bal Fe) were determined as a function of the temperature between −196°C and 600°C by means of a torque magnetometer. The sign of K1 is negative at −196°C and the magnitude is fairly large (e.g., −3 × 104 erg/cm3) for the most alloys examined. However, with increasing temperature, K1 crosses zero and changes its sign from negative to positive. It should be noted here that the temperature at which K1 crosses zero, TK1=0, differs distinguishably and ranges from −140°C to 200°C for each alloy composition. For the central composition of the Sendust alloy (9.6 wt% Si, 5.7 wt% Al, bal Fe), TK1=0 was found to be room temperature. No sign change of K1 took place in the case of the 7.4 wt% Si, 4.1 wt% Al, bal Fe alloy. The compositions at which K1 becomes zero are strongly temperature dependent. With increasing temperature, the compositional line of K1=0 moves to the area with rich A1 and less Si concentration in the Fe-Si-Al ternary alloy system. Temperature dependence of K1 for these alloys were discussed in connection with the two components of K1 consist of long range and short range order term in D03 phase.
  • 高橋 研, 富谷 忠史, 新井 英雄, 脇山 徳雄
    1986 年 10 巻 2 号 p. 225-228
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Temperature dependences of the magnetocrystalline anisotropy constant, K1, and the magnetostriction constants, λ100 and λ111 were determined for alloy single crystals with concentrations of 4.8 wt% Si, 5.0 wt% AI, bal Fe and 4.7 wt% Si, 3.8 wt% Al, bal Fe, respectively. The temperature dependence and the magnitude of K1 for each alloy were found to be completely different : K1=9.1 × 103 erg/cm3 for the former and 1.1 × 105 erg/cm3 for the latter alloys at room temperature, respectively. The values of λ100 and λ111 (× 10-6) at room temperature were found to be 4.8, 9.8 for the former and 7.8, 5.7 for the latter alloys. A unique diffraction line due to the existence of the D03 type of ordered structure was clearly observed for both alloys. From the results obtained, it may be concluded:
    1) The discrete change of the values of K1 exists at the phase boundary between α and α + D03 phases,
    ii) The magnitude of K1 for the alloys consisting of the D03 ordered phase is smaller than that of α + D03 phase.
  • 福永 博俊, 井原 慶太, 成田 賢仁
    1986 年 10 巻 2 号 p. 229-232
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Effects of crystallization conditions on magnetic properties have been investigated in amorphous Nd-Fe-B ribbons. Amorphous Nd15Fe75B10 ribbons were obtained by the single roller quenching technique. These ribbons, which have improved ductility and tensile strength, are soft magnetically in the as-prepared state and can be hardened by crystallization. It is found that short time annealing at high temperature is desirable for crystallization to obtain good hard magnetic properties. X-ray diffraction analyses and SEM observations have revealed that flash crystallization results in precipitation of sub-micron Nd2Fe14B micro-crystals whose sizes are nearly that of a single domain particle, and in extremely high coercive force. Excessive annealing at high temperature causes growth of crystallites and reduction of coercive force. The ribbons crystallized in the best condition are magnetically isotropic and have Br of 7kG and (BH)max of 10.2 MGOe when magnetized by a pulse field of about 30 kOe.
  • 八木 正昭, 森本 耕一郎, 八幡 誠朗
    1986 年 10 巻 2 号 p. 233-236
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Pr-Co binary ribbons with 11.1∼17.3 at% Pr were produced by rapid quenching techniques. The samples were melted and quenched in Ar gas atmosphere to avoid oxidation. A maximum coercivity of about 10 kOe was obtained for 17.3 at% Pr-Co ribbons (approximately the stoichiometric content of PrCo5), which was twice the value of sintered PrCo5 magnets. Oxygen content of these ribbons was 300∼500 ppm (by weight), less than about 1/10 the content of sintered magnets. These 17.3 at% Pr-Co ribbons were magnetically and chemically stable under atmospheric conditions for a 30 month period.
非晶質材料
  • 宮崎 照宣, 楊 興波, 高倉 敬一, 高橋 実
    1986 年 10 巻 2 号 p. 237-240
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    The structural analysis and investigation of magnetic properties were carried out on rapidly quenched Fe100-xSmx (10.5≤x≤80) alloys. Amorphous alloys were fabricated in a wide composition range from x=17 to 72.5. The composition dependence of Curie temperature and magnetization was found to be similar to that of amorphous Fe-(Nd, Pr) alloys and could be considered to be caused by the change in short-range atomic order with Sm concentration. A maximum coercive force of about 1.1 kOe at 300 K and 12 kOe at 77 K is obtained in x=40 alloy. The rapid decrease in coercive force on raising temperature can be explained by the wall pinning model proposed by Gaunt. After heating the amorphous alloys up to 900 K, they transform into metastable Fe5Sm (Tc=465 K) + α-Fe (x<20), unknown metastable phase (Tc=555 K) + α-Fe (20≤x≤33.3) and Fe2Sm (Tc=670 K) +Sm (x≥40).
  • 石尾 俊二, 藤倉 昌浩, 高橋 実
    1986 年 10 巻 2 号 p. 241-244
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Magnetic moment m, Curie temperature Tc, density ρ and Young's modulus ES of amorphous Mn-Y, Fe-Y, Co-Y, (Fe-Mn)80Y20 and (Fe-Co)80Y20 alloys fabricated by rapid quenching have been measured to make clear microstructures of amorphous alloys. Detailed comparison of m, Tc, ρ and ES between amorphous alloys and corresponding crystalline compounds, and a structural analysis by X-ray diffraction reveal a close correlation of an atomic short range order of both states, which is especially found in alloys with Y content less than 30at%. A structural variation between 30 and 40 at%Y in the Fe-Y amorphous alloys is also indicated by the composition dependence of m, Tc, ρ, ES and by X-ray analysis.
  • 李 佐宜, 張 礼君, 桜井 良文
    1986 年 10 巻 2 号 p. 245-248
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Amorphous magnetic films have unusually large extraordinary Hall coefficients. We prepared Sm-Co amorphous films with planar or perpendicular magnetization and studied the galvanomagnetic effect in these films. In this paper we report the Sm concentration dependence of electrical resistivity ρ, Hall resistivity ρH, Hall sensitivity S and Hall voltage VH P-P. We found that ρH is large because of the large saturation magnetization Ms and electrical resistivity ρ. The maximum value of ρH is 9.0 μΩ-cm at 15 atm. % Sm. We also studied the magnetoresistance of these films.
  • 早川 正俊, 林 和彦, 落合 祥隆, 松田 秀樹, 石川 理, 阿蘇 興一
    1986 年 10 巻 2 号 p. 249-252
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    The plastic flow has been investigated for Co-base amorphous alloys with some additive elements, Fe3Co71Si8B16M2 from creep measurement employing a constant heating rate method near the glass transition temperature. The activation energy in the creep process was found to be proportional to the atomic volume of the additive elements which were determined from the Goldschmidt radius. The observed activation energy was changed from 1.92 eV to 2.53 eV in Co (1.25 Å) and Nb (1.47 Å), respectively.
    The field induced anisotropy energy Ku hes been measured for the same alloy series. It was found that Ku decreased with the increasing of the atomic volume of the non-magnetic additive elements. In the case of nearly the same atomic volume of the additive elements, Ku seems to depend on the strength of the magnetic interaction. From these results, the degree of the rearrangement of the atoms and the magnetic interaction between magnetic atoms play a dominant role in the field induced magnetic anisotropy.
  • 木下 文宏, ローゲル マルムヘルム, 真部 利裕, 川本 浩, 毛利 佳年雄, 山崎 二郎
    1986 年 10 巻 2 号 p. 253-258
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Magnetic properties of amorphous magnetostrictive FeCoSiB-alloy wires, made by the inwater quenching technique, were studied. Domain pattern observation on the wire surface was made as a function of alloy composition and of applied magnetic field and tensile stress along the wire axis. The domain pattern was found to disapper at an axial field of 40 Oe and a tensile stress of about 12 kg/mm2. The residual stress is estimated to be 4-10 kg/mm2. Large Barkhausen and Matteucci voltage pulses and domain nucleation field in Fe77.5Si7.5B15 wires were found to decrease to zero at a compressive stress of 5 kg/mm2.
磁性体物理
  • 井上 光輝, 加島 篤, 蒔田 昭彦, 見山 友裕, 藤井 壽崇
    1986 年 10 巻 2 号 p. 259-264
    発行日: 1986/03/31
    公開日: 2007/12/27
    ジャーナル オープンアクセス
    Magnetoelastic waves (MEWs) propagating in a thin conductive magnetostrictive slab were investigated theoretically taking account of the micro-eddy current contribution. The analysis was performed under the assumption that the medium is amorphous (isotropic elasticity) but has a uniaxial magnetic anisotropy in the slab plane. MEWs in this configuration are three fundamental modes: Lamb-type wave of the extensional mode (EMEW), SH-type wave (SMEW) and Lamb-type wave of the flexural mode (FMEW). The microeddy current crucially affected the propagation properties, thereby increasing the propagation loss as well as decreasing the controllable MEW velocity with external magnetic field. The amounts of these quantities also varied depending strongly on the anisotropy orientation β for the above three wave modes, because the degree of coupling between the magnetization and the lattice through magnetoelastic interaction is different in each mode. The present analysis revealed that SMEW with β=45° is the most favorable for delay line application.
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