In order to prepare obliquely oriented tapes having a definite orientation angle, the LIPS (longitudinally oriented inside layer and perpendicularly oriented at surface layer) orienting method was improved. The permanent magnets pairs of the LIPS for perpendicular orientation were replaced by an electromagnet with long iron plates for extension of magnetic poles. Obliquely oriented tapes are easily prepared by choosing the coating speed and the drying condition. Coating sdried in the perpendicular field with intensity gradient are found not to be oriented perpendicularly but obliquely. It is considered that inner-layer particles are more easily displaced by the field gradient force than surface particles because of the effect of the viscosity gradient in the coating drying process.

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It has been reported that high-density and widebandwidth characteristics are obtained by using a combination of a ring head and obliquely oriented metal evaporated magnetic recording tapes. Therefore, we developed new equipment for the preparation of obliquely oriented tapes of γ-Fe₂O₃ particles, and examined themorphology, magnetic properties, and wavelength response of the tapes. The experimental results showed that a tape obliquely oriented at 30°has the highest-output and widest-bandwidth characteristics.

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Co-Cr perpendicular magnetic films were sputterdeposited at extraordinarily high Ar gas pressures over 10 Pa with discharge voltages lower than 300 V. When the films were deposited on glasss ubstrates at Ar gas pressures higher than 10 Pa, they showed columnar structures with large grain sizes and poor crystal orientations accompanied by large squarenessin the in-plane M-H loop. When Ti underlayers with a high perpendicular orientation of the c-axis Δθ₅₀∼5° were introduced, high crystal orientation (Δθ₅₀<5°) and small squareness ratio (M_r///M_s∼0.2) were obtained for Co-Cr films deposited at 50 Pa. The films showed fine columnar structures with distinct grains about 50nmin diameter for 200-nmthick films. This type of films thought to be a possible candidate fora high-density perpendicularrecording medium with an improved preparation method in discharge characteristics.

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The recording properties of Co-based alloy heatr treated media using carbon substrates with high heat resistance wereinvestigated. For media with the same H_c, the amplitude and the media noise of the CoCrTa media were lower than those of CoNiCr and CoCrPt media, because of the lower B_rδ (Where δ is the thickness of the Co-based alloy layer). For CoNiCr media with the same B_rδ, the media noise decreased with increasing H_c, namely, with increasing heat treatment temperature. Rotational hysteresis loss analysis uslng a highly sensitive torque magnetometer and high resolution scanning transmission electron microscopy (HRSTEM) analysis showed that the values of H_c/H_kgrain increased to 0.44 with increaslng H_c, and that the Cr concentration in the grain boundaries of CoNiCr alsoincreased. Therefore, it is considered that the reduction in noise was achievedas a result of the decrease in exchange coupling between grains.

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Experimental characterization of the magnetic anisotropy field of grains H_k^grain and the intergranular magnetic coupling for (Co₈₆Cr₁₂Ta₂)_100-xPt_x thin film media was carriedout by analyses of the magnetic torque and ΔM plot. The magmitude of H_k^grain gradually increases from about 4kOe to about 8kOe with increasing Pt content up to 8 at%, mainlybecause of the increase in magnetocrystalline anisotropy. On the other hand, the ratio of the coercive force H_c to H_k^grain changes from about 0.2 to about 0.3, depending on the Pt content and substrate temperature at the time of the film's fabrication. It was clarfied that the difference of the ratio of H_c to H_k^grain in the examined media depends mainly on the difference in the strength of the intergranular exchange coupling. On the other hand, it is suggested that the knowledge of H_k^grain should be taken into account, in order to clarify how much the intergranular magnetic coupling influences the coercive force through the analysis of the ΔM plot.

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Henkel plots arelinearized when the field −αM compensating for the interparticle meaninteraction field is applied during VSM measurements. By this method, the mean field constants α were estimated to be about 0 and 0.2 for longitudinally oriented Baferrite particulate media with squarenesses of 0.5 and 0.8, respectively. To consider the interparticle magnetic interaction in the recording simulation, the mean field was introduced into our simulator based on a finite element method and the curling magnetization switching model. By simulation analysis, it was shown that the reproducing voltage atlow recording densities was increased by the positive mean field in a longitudinally oriented Ba-ferrite medium. On the other hand, in a perpendicularly oriented medium, the high-density performance was greatly improved by the mean field.

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Substrate bias-Sputtered FeTaN/SiO₂ multilayer films with double structure were prepared with electrically insulated thick FeTaN layers, each of which layer consisted of thin FeTaN layers where the anisotropy direction of each FeTaN layer was different from that of the adjacent FeTaN layer. Such films, hereafter called “Double-structured substrate Biassputtered Multilayer (DSBM) films” , were developed for their potential use in magnetic heads. Doublestructured laminated (DSL) heads composed of the DSBM films sandwiched with ceramic substrates have been developed. These heads, which show as good recording characteristics as the heads composed of conventional laminated FeTaN films (CL heads) when used with high-coercivity tape, exhibit superior reproduction characteristics at high frequencies to that of the CL heads.

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Noise-after-write has hen reported in thin-film heads, although the sources have not yet been identified. To discover these noise sources, I observed the manetic domain structum conversions after writing with an electron microscope, The magnetic domain observation consisted of lock-in image processing for back-scattered electron contraat (Type II), using a JEOL 2000FX II 200 kV electron microscope. Thin-film heads were excited with a 10 mA_p-p, 100 kHz drive current. The magnetic domains in the upper yokes of the heads were obgerved after 60 mA_p-p write operations. The head that had the highest noise probability of 5.2 × 10^-2 exhibited radial walls oentered at the backgap closure because af stress. Its magnetic domain configuration after writing was severely converted. The head with the lowest noise probability of 1.6 × 10^-4 exhibited a normal closure domain configuration, with very little conversion. These results indicate that noise-after-write is generated mainly near the backgap closure.

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Perpendicular magnetic recording is one method of achieving high-density recording. In perpendicular magnetic recording using a single-pole-type (SPT) head, it is necessary to use a main pole film that works stably. In this respect, use of a single-layered main pole film has a serious limitation because of its domain structure. On the other hand, a multilayered main poleisthought to have no limitation,because the closure domain will be eliminated by magnetic coupling. However, SPT headsusing multilayered thin nlms often show instability in the reproduction process. We found that theinstability could be removed by applying a dc magnetic field to the multilayered main pole. The stressin the multilayered film was related to theinstabilityin the head's behavior. We also showed that an underlayer between the magnetic layer sand the substrate is necessary to eleminate the stress in multilayered films.

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The linear recording density in perpendicular magnetic recording is limited by the thickness of the main pole in a single-pole head. In order to raise the practical reproduction resolution, a thin main pole film is indispensable. Fe-Si film has large saturation magnetization, and goods of tmagnetic properties are obtained in the thickness range from 50 nm to 200 nm. However, as the film thickness decreases below 100 nm, the domain wall structure and the domain configuration change from Bloch type wall and the closure-domain state. A head with this thin film as the main pole shows unstable readback output and poor resolution. The authors therefore adopted as the main pole an Fe-Si/SiO₂ multi-layered film whose domain structure was different from that of an Fe-Si single-layer film. As a result, the output stability and the high-density response were improved by the control of the inter-layer thickness and the number of magnetic layers.

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The effect of shape on the bias field of an Ni-Fe/Ti/Co-Zr-Mo trilayer MR element is discussed in relation to the aim ofc ontrolling the bias field of an MR head. In the case of an Ni-Fe single film, the field at half-maximum MR coefficient was found to be proportional to the thickness and reclprocal height. In the case of a trilayer MR element, the saturation bias field was found to be proportional to the Co-Zr-Mo thickness. The bias field was saturated at smaller sense currents, and the saturation bias field increased as the Ti thickness decreased. The use of a Co-Zr-Mo surface oxidation layer instead of a Ti film in the trilayer MR element was effective because the element became a uniform and thin film.

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The read-write characteristics of thin-film heads with an NiFe/CoNiFe laminated upper pole are studied. Compared with NiFe heads, NiFe/CoNiFe laminated heads are better able to suppress loss of output and increase in disk noise, and provide better overwrite characteristics. Comparison of experimental and calculated results indicates that pole saturation causes an increase in the transition length, because of the field gradient decrease, which results in an output decrease. The decrease in head efnciency due to the increase in the CoNiFe thickness is negligible if the latter thickness is less than 20% of that of the upper pole. NiFe/CoNiFe laminated heads are deemed promising for high-linear-density recording.

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The innuence of insulators of laminated heads on recording patterns was investigated by using the Bitter method and computer simulations. Some unrecorded areas exist on a recording track, and these correspond to the positions of insulators on the trailing side. An unrecorded area becomes wider with an increase in the magnetomotive force. The size of an unrecorded area depends on the insulator's thickness and the media's coercive force. These results were confirmed by simulations using thefinite element method.

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We investigated the influence of the vibration characteristics of a head/diskin contact recording. The frequency response function (FRF) and Q factor were used to analyze the vibration of the head-disk interface motionin a drag test. The effect of the natural frequencies of the various disks is examined. The Q factor, obtained from the FRF of the vibration of the head-disk interface motion, is related to the durability on drag test.

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A Co-based laminated amorphous film head was tested in a rotary drum system at relative velocities from 5.8 m/s to 69.6 m/s. Sufficient contact was maintained between the head and tape even at relative velocitiesas high as 69.6m/s. A frequency loss in the head was caused by playback output and recording sensitivity. The experimental data agreed well with theloss calculated from the frequency dependence of the initial permeability of the magnetic core by using the magnetic circuit method. A frequency loss of 180 MHz / 1.25 MHz was about 16 dB, and was independent of the magnetic field level.

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A head-disk interface (HDI) analyzer for a highdensity FDD was improved. This equipment consists of a high-speed shutter camera and a highly sensitive image processor. It makesit possible to evaluate dynamic spacing fluctuations by analysis of interference fringe patterns on both sides of a floppy disk (FD). With this equipment, the dynamic motions of an up-head slider and FD were observed. Moreover, it was shown that the surface roughness of the FD affected the head-touch and that a smoother disk surface caused larger spacing variation. This result indicates that an appropriate surface roughness is required in a FD so as to maintain reliability in a high-density FDD.

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In an investigation of tape/slurry texturing for an NiP/Al alloy substrate, it was found that disks textured with alumina slurry showed a better glide performance than those textured with diamond slurry. A carbon protective layer sputtered by uslng argon gas or argon/methane gas also improved the tribological properties of the disks, leading to enhanced durability. Disks textured with alumina slurry and sputtered with a carbon protective layer by using argon/methane gas performed well in both a glide test at a flying height of 0.05 μm and a CSS cycle test with a thin-film head.

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The magneto-optical spectra (σ_xx and ωσ_xy) were investigated in the photon energy range of 1.2 to 4.6 eV for Ni₃Fe thin hlms before and after heat treatment. It was found that both spectra changed dramatically as a result of the heat treatment. The σ_xx and ωσ_xy spectra of Ni₃Fe thin films were reduced by the transition from disorder toorder. The joint density of states for both ordered and disordered states of Ni₃Fe were also calculated, and compared with the experimental data.

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By means of the alternating ion-beam-sputtering method, Al³⁺ or Ga³⁺ ions were successfully substituted for Fe³⁺ ions in a Bi₃Fe₅O₁₂ (BIG) film. The effects due to substitution were confirmed by measurements of the lattice constant, ferromagnetic resonance field, and magnetic moment. The lattice constant and saturation magnetization of BIG can be adjusted by Al- or Ga-substitution, which is analogous to Al- or Ga-substituted YIG. The magnetic anisotropy of a BIG film can be changed from the easy-plane type to the perpendicular uniaxial type by Al- or Ga-substitution. This uniaxial anisotropy is mainly attributed to the stress-induced anisotropy.

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Repeated writing and erasing characteristics were measured on quadrilayer MnBi magneto-optical disks. The carrier levels decreased with the number of writing cycles. We found that this degradation was caused by decomposition of the MnBi lowtemperature phase and by the change from the lowtemperature phase to the high-temparature phase in the writing process. The rates of decomposition and phase change decreased at a high linear velocity and alow write power. The reliability of the MnBi writing cycle can be improved by optimization of the disk's heat structure and recording conditions.

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The degradation processdue to multiple erasing in Pt/Co magneto-optical disks was studied by measuring the magnetic property of the degraded region and by observing the deformation of the substrate. The media noise was found toincrease at a lower number of erasing cycles than that needed to effect a decrease in the carrier level. The increase in the media noise is attributed to the decrease in the perpendicular magnetic anisotropy (K_u) of the Pt/Co multilayered film. The decrease in the carrier level is attributed to the reduction in the residual Kerr rotation due to a further decrease in K_u, and to the deformation of the substrate.

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The effect of adding Nd to a RE-TM Blm on the disk's magneto-optical and read/write properties was investigated. It was found that as the amount of Nd was increased, the C/N ratio improved at a wavelength of 532nm. In spite of an increase in the Kerr rotation angle, the carrier level was little improved. This fact can be explained by the disk's magnetooptical characteristics, as a result of which the Kerr ellipticity angle decreased in the short-wavelength region as Nd was increased. Thus the value of the figure of merit was not improved. The improvement in the C/N ratio was due to a decrease in the noise level.

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The dependence of erasenoise on magneto-optical (MO) film thickness was studiedin order to clarify the origin of such noise in amorphous TbFeCoTi MO media. Erase noises were measured from the RF differential signals of an MO head, which represented local variations in MO film Kerr rotations. These signal levels were decreased by increasing the MO film thickness and by increasing the SiN under-layer sputter etching. The reductions in noise corresponded to increases in the perpendicular magnetic anisotropy constant K_u for the MO film. Further, higher read power irradiation to MO films with an external bias magnetic field lowered the noise levels drastically. The magnetization fluctuation at the initial layer of the MO film growth was discussed to explain the orlgln of the noises.

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Mark formation mechanisms and R/W characteristics were investigated with a R/W tester and a polarized microscope for two kinds of exchange-coupled magneto-optical disk consistirlg of a reading layer and a writing layer. In one of the disks (a regularmode disk), recorded marks in the reading layer were transcribed to the writing layer, and vice versa in the other (an inverse-mode disk). For the regular-mode disks, the characteristics of the carrier levels in relataion to the writing power showed two stages, corresponding to ring domain and full domains. The ring domains appeared when the writing power was low, and were caused by the magnetics field near the T_c radius in the writing layer. The full domains appcared when the writig power was high, because the anisotropic field in the reading layer decreased sufficienty for this to occur.
For inverse-mode disks, only one stage was observed. This is because marks formed by the Curiepoint writing process in the writing layer, were transcribed to the reading layer.

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Optical enhancement conditions and read/write characteristics for exchange-coupled double-layer magneto-optical (MO) disks were investigated. It was found that the figure of merit (R^(1/2)·θ_k) for an MO disk with a thick (60-nm) magnetic layer is comparable with that for a conventional MO disk with a thin (20-nm) magnetic layer, The writing noise level of the thick-magnetic-layered MO disk is markedly lower (2∼5dB) than that of the conventional one. An exchange-coupled double-layer (GdFeCo30-nm/TbFeCo30-nm) MO disk, which has a large Kerr rotation, moderate reflectivity, and low noise level, is suitable as a high-performance medium.
This MO disk shows a C/N ratio of 45 dB for a wavelength of 680 nm, and a mark length of 0.67 μm when a 1.2-μm track pitch polycarbonate substrate is used.

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The magnetic after effect constant (S_v), the distribution of the anisotropy field (H_A), and the rotational hysteresis integral (R_h) were measured for M-type hexagonal strontium ferrite (SrM) fine particles having various average particle diameter (D) and coercive force (H_cJ). The relationships between S_v, the activation volume (v), H_cJ, H_A, and R_h were studied, as well as the milling effects. S_v is constant and independent of the magnetic field. ln S_v vary in proportion to ln H_cJ, and the relation H_cJ∝v^-2 is obtained in SrM particles which were subjected to less milling effect. S_v increases and v decreases for SrM fine particles (D=0.3μm) whose H_A is widely distributed by milling, even though H_cJ decreases markedly. S_v and v are related to the distribution of H_A. As H_cJ increases, R_h and v decreases, which in dicates that magnetization reversalmechanism of SrM line particles approaches to that of the coherent rotation mode.

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Submicron-sizedparticles of M-type Sr-ferrite were obtained from fine Fe₂O₃ and precipitated SrCO₃. The magnetic properties of the powder were σ_s=71 emu/g and H_cj=5.5 k0e. The H_cj of the powder was reduced to less than 40% of the initial value by dry vibration milling. SEM observation showed that the primary particle size distribution was not much different from that in the initialstate. Crystal distortion was determined by XRD investigation, using the method of Warren and Averbach. The torque curve of the milled powder was measured by using a highly sensitive torque magnetometer. The dependence of K₂/K₁ on the measuring magnetic field was increased according to the crystal distortion by milling. The Möessbauer absorption effect was also measured. Submicron particles were analyzed in comparison with coarse Sr-ferrite particles (3μm) by a conventional breaking-down process.

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The microstructures of Sm₂Fe₁₇N_x (0<x<6 )powders were observed by transmission electron microscopy (TEM). Sm₂Fe₁₇N_2.3 powders nitrided in N₂ gas have high densities of dislocations formed by lattice expansion. Sm₂Fe₁₇N_x powders nitrided in mixed gas of NH₃ and H₂(3<x<6)have cell-like structures. The dislocation density increases and the cell diameter decreases with increasing N content, and Sm₂Fe₁₇N_5.9 powders consist of Sm₂Fe₁₇N_x microcrystalline grains of 30∼50nm in diameter surrounded by an amorphous phase. Sm₂Fe₁₇ powders nitrided at above 600°C disproportionate into SmN and α-Fe phases with the sizes of 10∼20nm.

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An experiment was carried out to investigate the magnetic and physical properties of (Sm_1-xNd_x)₂-(Fe_0.8Co_0.2)₁₇N_y (x=0∼0.5) in which y value is 3. The anisotropy field (H_A) in (Sm_1-xNd_x)₂(Fe_0.8Co_0.2)₁₇N_y compounds decreased linearly with increasing x value, while the saturation magnetization (J_s) increased. It was found that H_A amd J_s of an (Sm_0.9Nd_0.1)₂(Fe_0.8Co_0.2)₁₇N_3.07 compound were 10.4 MA/m and 193.6×10^-6Wb · m/kg, respectively. Anisotropic epoxy-bonded magnets were prepared from (Sm_0.9Nd_0.1)₂(Fe_0.8Co_0.2)₁₇N_3.07 powder of about 3∼5μm by a compressing molding process. The magnetic properties of a typical bonded magnet were (BH)_max=101.8 kJ/m³, J_r=0.89 T, H_cJ=394 kA/m, and H_cB=314 kA/m. Magnetization jumps were observed on the hysteresis loop of a bonded magnet at 7K.

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The standard method for measuring magnetization, using a closed magnetic circuit, is inapplicable to rare earth magnet materials with very high coercivity. An open magnetic circuit method in a steady high magnetic field is therefore examined, where a correction for a demagnetizing field is important. We measured hysteresis curves for some commercial rare earth magnet materials by using cylindrical samples with various dimension ratios. The correction for the demagnetizing field gives a reasonable result for bonded magnets, whereas even the intrinsic coercivity seems to depend on the sample shape for sintered magnets. Therefore, it is necessary to reconsider the correction for the demagnetizing field and also the standard specifications of rare earth magnet materials.

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The workability of hot bending for hot rolled Pr-Fe-B-Cu magnets was investigated. Under optimum bending conditions, Pr-Fe-B-Cu magnets are bent without cracking. The workability is improved at higher temperatures and lower strain rates. The deformation during the bending is derived from the sliding of the grain boundary. Addition of Cu enables the magnets to be worked at a higher strain rate, because of the increased wettability and grain refinement. Arc-shaped magnets were formed by die bending without deterioration of the magnetic properties. Further, radially oriented ring magnets were produced by bonding these magnets with a liquid phase at a high temperature.

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The magnetic properties of Nd-(FeCoNiTi)-B and Nd-Fe-B-type sintered magnets in thin sheet form were investigated from the standpoint of the deterioration in coercivity caused by machining. It was found that the thickness of a deteriorated layer of an Nd-(FeCoNiTi)-B-type magnet is smaller than that of an Nd-Fe-B-type magnet. This phenomenon is explained in terms of the toughness and fine-grained structure of an Nd-(FeCoNiTi)-B magnet.
It is suggested that an Nd-(FeCoNiTi)-B magnet may be applied as a 50-μm-thick sheet.

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High-energ yextrusion-molded magnets, composed of isotropic Nd-Fe-B powder and Nylon-12, were developed. The mechanical properties and the degree in packing of the extruded products were investigated. With proper adjustment of the magnetic powder distribution, the extruded products contained 78 vol% magnetic powder and generated a (BH)_max of 9.9 MGOe. The shearing strength of the extruded products is 7.83 kgf/mm², which is about 1.6 times that of compression-molded magnets with the same formulation. The porosity fraction in the extruded products was 1.1%, which is significantly less than that of compression-molded magnets.

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The magnetization and Curie temperature of rapidly quenched (Gd_0.7M_0.3)₈₀Si₁₂B₂(M=Y, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al) amorphous alloys were investigated. The Curie temperatures of alloys with M=Mn, Fe are hjgher about 70 K and 120 K than that of Gd₈₀Si₁₂B₈ amorphous alloy. The magnetic moments of Mn, Fe, and Co atoms are 2, 1, and 1 μ_B, respectively. These magnetic moment are anti-parallel to that of Gd atoms. The magnetic momnent of Ni atoms almost disappears. Furthermore, the magnetic moments of Y and V atoms are 1.7 and 2.1 μ_B, respectively. The magnetic moment of Y atoms is anti-parallel to that of Gd atoms, while that of V atotms is parallel to that of Gd atoms. We conclude that alloys with non-magnetic elements M exhibit asperomagnetism in which the Gd moments are distributed, while alloys with magnetic elements M have ferri magnetic order.

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The magnetic properties of ordered bcc FeRh_1-xM_x alloys (M=Fe, Co, Ni, Pd, Ir and Pt) were studied, and the correlations among the antiferromagnetic-ferromagnetic transition temperature T₀, the Curie temperature, magnetization, and lattice constant were investigated. Substitution of the 3d element M for Rh diminishes the transition temperature T₀, since the large magnetic moment of the M atom stabilizes the ferromagnetism. Moreover, first-order antiferromagnetic-paramagnetic transition was observed in an FeRh_1-xIr_x system. The mechanism of those first-order phase transitions can be explained phenomenologically by introducing magneto-volume coupling into the model based on the SCR theory. The ground state properties of FeRh and FeRh_1-xPd_x are well explained by first-principle band calculations based on the linearized muffin-tin orbital method.

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Fe_100-xN_x thin films were prepared by RF sputtering in low plasma density of nitrogen. All the films, in which 0≤x≤35 at%, consisted of a single and metastable phase of a body-centered cubic structure. The saturation magnetization seemed to follow the slater-Pauling curve with respect to the nitrogen concentration. In the films, the Fe atoms at the nearest neighbors of a nitrogen atom were found to behave like Co atoms.

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The concept of the magneto-impedance effect (MI effect) in magnetic amorphous wires is put forward. At certain frequencies, the wire impedance is highly responsive to magnetic properties, owing to the dependency of the skin depth on magnetic permeability. The theoretical analysis of the MI effect is based on the exact expression for the impedance of a magnetic wire in which the dynamic permeability related to domain wall displacements is damped by microscopic eddy currents. The circular domain structure typical of negative magnetostrictive amorphous wires is considered. In this case, the penetration depth depends on the circumferential permeability, which is a sensitive function of a dc longitudinal field. The theoretical approach is found to account satisfactorily for the existing experimental data on the magneto-impedance characteristics of negative magnetostrictive amorphous wires. In the frequency region where the skin depth is comparable with the wire radius, the MI ratio can reach more than 50% in magnetic fields of the order of the anisotropy field.

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Chaotic oscillation of a domain wall is shown by computer simulation for a differential equation that includes terms for the non-linear force of restitution and eddy current damping. Chaotic oscillation involves irregular phenomena (the error or noise in magnetic recording systems) and the energy loss. The bifurcation diagram of magnetic domain-wall motion is a useful method for investigating chaos. The external magnetic field is an important parameter in the design of magnetic devices. The bifurcation diagram of the wall velocity is calculated on the amplitude of the external magnetic field. The route to chaos is the bifurcation via periods 2, 3, 4, and 5 from period-1 oscillation. The periodic windows and the chaotic region appear alternately. The energy loss caused by the domain-wall motion is calculated. The value of the energy loss in chaotic motion is larger than the value in regular motion, in spite of their having the same damping coefficient. Chaotic motion is a new mechanism that causes an increasein the energy loss.

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We developed a Mott analyzer of the spherical accelerator type, to measure the spin polarization of electrons extracted from a ferro-magnetic tip or a GaAs sample. This analyzer was designed for a low-acceleration voltage (40 kV). Inelastic scattered electrons are retarded by spherical electrodes. This paper reports the spin polarization of electrons extracted from negative electron affinity (NEA)-GaAs. It was found that this type of Mott analyzer involves a few problems to be solved.

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Ferromagnetic resonance was studied in 1000-Å- thick Co films evaporated on sapphire, glass, or MgO substrates. An effective uniaxial anisotropy field (H_{k eff}) of - 16.27 kOe and a gyromagnetic ratio (γ/2π) of 3.10 GHz/kOe were obtained for a film on sapphire. Assuming a saturation magnetization (4πM) of 17.58 kG, we derived a small intrinsic per- pendicular anisotropy field (H_{k eff}+4πM) of 1.31 kOe. The measured resonance fields are close to those of a polycrystal with no orientation rather than a (001)- oriented hcp film.

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The sputtered (Fe_100-YCo_Y)_100-XTi_X (0≤X≤5, 23≤Y≤53) films were studied on the dependence of soft magnetic properties on composition, annealing temperature, and film thickness. After annealing at 823 K for 3600 s, the permeabilities of the films exhibit a maximum of 1650 at (Fe₆₉Co₃₁)₉₇Ti₃. The corresponding saturation magnetic flux density is 2.2 T. When the lattice constant of Fe-Co film expands by about 0.2%. the permeability reaches a maximum. When the film thickness is reached to 1357 nm, the permeability decreases to 500. The permeability of an (Fe₆₉Co₃₁)₉₇Ti₃/Zn0 multilayered film annealed at 773 K for 3600 s is 1100; this is about twice of the permeability of a single-layer film.

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Fe-M-(O, F) (M=Si, Mg, Y, Zr, Ca, Al) films were prepared by co-sputtering of Fe and ceramic targets. These films have a network-like structure composed of metallic fine grains with a diameter of about 50∼100Å and ceramic-like boundaries. Those films that consist of bcc-Fe grains have soft magnetic properties and low magnetostriction in the as-deposited state. Their permeability has a good frequency response, which seems to be attributable to the reduction of eddy current losses by the highly resistive boundaries.

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The soft magnetic properties of electrodeposited CoNiFe films were studied. Films composed of 30∼50 wt%Co-23∼35 wt%Ni-25∼35 wt%Fe alloy with a high saturation magnetization of more than 1.5 T show a low coercivity of less than 0.2 Oe. A film composed of 40Co-30Ni-30Fe alloy and having an fcc phase structure with small bcc phase, which was created by annealing at 300°C, has excellent soft-magnetic properties (H_c=0.06 Oe, μ=3200, B_s= 1.8 T). This bcc phase makes an appearance during the first stage of crystallization at 287°C. The structure is thermally unstable, and is due to a special feature of electrodeposition. During the annealing, H₂O, H₂, and CO₂ were released from the film, but the patterns of generation of these gases bear little relationship to the DSC pattern.

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It was proved that the magnetic properties, structure, and residual stress of Fe films electrodeposited from iron(II) chloride solution were strongly dependent on the electrodepositing conditions of the applied current density and the solution temperature. The applied current was varied from 5 to 100 mA/cm² and the solution temperature was also varied from 20°C to 60°C. In these conditions, lower coercive forces was obtained at lower applied current densities and higher solution temperatures, and it appear. ed that the residual stress was the dominant factor in the magnetic properties of the films. The value of the Q-factor of a coil composed of Cu-wire coated with these Fe films was measured, and the results demonstrated that the Q-factor varied over the range of depositing conditions investigated and Q-factor was dependent on the coercive force.

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A method for preparing Permalloy films electro deposited with a square pulse mode current was studied along with the soft magnetic properties of the films. The influence of three plating parameters (duty cycle ratio, frequency, and dc-bias) on the formation of film structures, alloy composition, and magnetic properties was investigated. It was found that films with μ_i≥4000 (max. 6000) and zero magnetostriction can be obtained with good reproducibility by pulse plating with a low duty cycle ratio. The characteristics of Permalloy electrodeposition with a square pulse current are discussed.

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Pure Ag, Cu, Ni, and Co films were prepared by vacuum evaporation on a LiNbO₃ single-crystal substrate excited by surface acoustic waves (SAW) at 45 MHz under various amplitude conditions. The surface morphology of the films and the SAW propagation properties during deposition were investigated in order to determine the influence of SAW excitation on the structural changes in the films. In the Ag and Cu films, the surface roughness R_a and the thickness d_p at which the SAW attenuation reached a maximum changed drastically as a function of the SAW amplitude, in contrast to the case for the Ni and Co films. Taking into account that d_p corresponds to the thickness at which the film structure changes from island to continuous, it was considered that SAW influences the initial stage of film growth and that a large SAW amplitude enhances the agglomeration of islands. By in situ monitoring of the propagation properties of SAW, microscopic structural changes were also found in the Ag and Cu films during the initial growth stage.

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The saturation magnetization M_s of polycrystalline iron thin films increased by approximately 10% after the films were treated by ion nitriding for about one hour. In the nitride treatment, we used the magnetron discharge method to increase the energy density of the discharge. The rate of increase in M_s was 21.2% after the iron thin film was nitrided under an NZg as pressure of 4.5 × 10^-2 Torr. Fe₁₆N₂, γ'-Fe₄N, ε-Fe₃N, ξ-Fe₂N, and α-Fe phases were detected by the X-ray diffraction method in nitrided thin films under various N₂ gas pressures. The saturation magnetization M_s of Fe₁₆N₂, calculated by using X-ray integrated intensity ratios, was 2210 emu/cc in the nitrided thin film under an N₂ gas pressure of 4.5 × 10^-2 Torr, and the M_s of Fe₁₆N₂, calculated by using X-ray integrated intensity ratios, was 1710 emu/cc in the nitrided thin film under an NZ gas pressure of 7.5 × l0^-2 Torr.

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This paper discusses the correlation between soft magnetic properties and microscopic magnetic structure in Co-(0∼6) at% Fe-(7∼10) at% Ta-N nanocrystalline films. Increase of the Fe content improves the soft magnetic properties of the films by decreasing the local anisotropy fluctuation. The temperature dependence of the coercive force indicates that the decrease in the magnetocrystalline anisotropy at room temperature due to the increase in the Fe content plays an important role in decreasing the local anisotropy fluctuation. Furthermore, with increasing Fe content, the film magnetostriction decreases, which suggests that the magnitude of the linear magnetostriction decreases. On the other hand, the uniaxial magnetic anisotropy energy K_u is reversibly induced by magnetic annealing in all films. With an increase in the Fe content from 0 to 6 at%, the magnitude of K_u gradually increases, and the K_u of the films containing 6 at%Fe is about twice as large as that of films without Fe.

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The effects of AI and N concentration on the structure and properties of Co_.95Fe_.05-Al-N films, prepared by RF reactive magnetron sputtering with (N₂+Ar) gases, have been studied. TEM observation reveals that nitrided films are composed of heterogeneous phases with a very fine network structure. It was found that the properties of films were determined mainly by the combination of Al and N concentrations. The coercivity of the films containing more than 10 at% Al decrease with increasing N content, even when the film thickness is more than 2μm. A steep increase in the resistivity and a slight decrease in the magnetization of films containing more than 15 at% Al are observed during the initial increase in the N concentration, and both resistivity and magnetization decrease rapidly when the N concentration is the same as that of Al. These anomalies are attributed to intergranular materials, indicating the presence of an Al-N rich-phase in these films.

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Fe-N films were deposited on glass substrates at room temperature by using a pulsed KrF excimer laser (wavelength = 248 nm. pulse width = 27 ns). The film composition and structure depend on the ambient N₂ pressure, the laser pulse energy, and the repetition rate. In order to understand the interaction between light-emitting ablated particles produced by excimer laser ablation of Fe and ambient N₂ gas, the dynamics of ablated plumes were investigated by means of a high-speed framing streak camera and time-resolved emission spectroscopy. Two distinct components of ablated particles were observed. One consists of a spherical plume with an average velocity of over 100 km/s, which is observed for about 300 ns from the laser irradiation. The other consists of a columnar plume with a maximum velocity of 22 km/s, which is observed for 1∼10μs. The velocity of Fe radicals depends on the N₂ pressure, which contributes to the form action the of Fe-N film.

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