巻号一覧
35 巻, 5 号
選択された号の論文の36件中1～36を表示しています
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一ノ瀬 昇1988 年 35 巻 5 号 p. 299-300
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリー超伝導セラミックスが発見されて一周年を迎えた。90Kという臨界温度(Tc)の高さから液体窒素温度で超伝導現象を利用することができ、産業界に及ぼすインパクトは計り知れないものがあると、この一年間、基礎研究、応用研究の両面から精力的な研究開発が進められてきた。この1月には金材研でBi-Sr-Ca-Cu-O系の新しい材料の発見もなされ、超伝導セラミックスの奥行きの深さを考えさせられる。この一年、物性の研究がいろいろの面から進められ超伝導機構の解明は着実に進んでいると考えられるが、材料的には従来の超伝導材料に比較してさほど進歩しているとも思えない状態にある。
本協会の講演特集「酸化物超伝導物質と材料」は昨年の秋季大会(京大会館 昭和62年11月10-13日)に引き続いて企画されたものであり、本年の春季大会(学士会館 昭和63年5月16-19日)の開催中に多数の参加のもとに盛大に行われた。本論文集は、各々の講演者にお願いして、総説、論文、論文速報の形でまとめて頂いたものであり、その時点においての最新の報告である。
内容の詳細については、各々の報告を参照して頂くことにして、講演内容を参考にしながら超伝導セラミックスについて2,3コメントしてみたい。抄録全体を表示PDF形式でダウンロード (282K) -
浅野 肇1988 年 35 巻 5 号 p. 301-304
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーSince the discovery of high-Tc superconductivity in the La-Ba-Cu-O system, many kinds of oxide-superconductors have been found out: the 40K-superconductor La2-xAxCuO4 (A = Ca, Sr and Ba), the 90K-superconductor RBa2Cu3O7-y (R = Y and most of the lanthanide elements) and newly discovered Bi- and Ti-oxide systems. These compounds, together with BaPb1-xBixO3 of Tc = 12K, are based on the perovskite-related structure. The present paper reviews common structural features in these oxide-superconductors.抄録全体を表示PDF形式でダウンロード (2250K) -
坂東 尚周1988 年 35 巻 5 号 p. 305-312
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーBy means of the activated reactive evaporation, single crystal thin films of YBa2Cu3O7-x with their (001) and (110) planes parallel to the corresponding surfaces of SrTiO3 have been obtained successfully. The substrate temperature was kept at 500650°C and a subsequent in-situ oxidation treatment was performed below the growth temperature. An ac-resistive measurement for a (001) film 1000A thick gave a sharp superconducting transition with an end point of 90.2K and ΔTc(10-90%)=1.7K. The highest Jc of 4×106 A/cm2 at 77K was achieved for the thickness. From a complex susceptibility measurement we confirmed the Meissner effect as well as the structural uniformity of the films prepared. For the films grown on SrTiO3(110), the RHEED patterns have shown that the films have the (110) or (103) orientation depending on the substrate temperature.抄録全体を表示PDF形式でダウンロード (1048K) -
小松 啓, 林 成行, 井上 哲夫1988 年 35 巻 5 号 p. 313-317
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe methods of single crystal growth of well-qualified high-Tc Superconductors [La2CuO4 type and ABa2Cu3O7-δ (A=Y, Eu, Er, Dy, Ho, Yb)] were described. The growth mechanism of these crystals was analysed to be a lateral growth type by surface microtopographic observation of as-grown surfaces. The crystals show many spiral layers with giant Burgers vector, whose origin was discussed in terms of the crystal habit.抄録全体を表示PDF形式でダウンロード (3627K) -
松田 昭一1988 年 35 巻 5 号 p. 318-320
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe transport Jc of YBa2Cu3Ox increased with sintering temperature and after a maximum of 1100 A/cm2 turned to decrease. Microcracks and second phases such as BaCuO2 and CuO along grain boundaries were observed. Magnetizatin measurement showed that single crystalline YBa2Cu3Ox made by a melt technique was almost free from weak links as differed from sintered samples. Clear specific heat jump at Tc was observed for YBa2Cu3Ox giving about (Δ Cp/Tc) of 52 mJ/mole·K2. Cu 2p core-level XPS spectra of YBa2Cu3Ox exibited a two peak structure. The higher (satellite) and lower (main) binding energy corresponded respectively to 2p3d9 and 2p3d10 L final-state configurations.抄録全体を表示PDF形式でダウンロード (357K) -
河野 宰1988 年 35 巻 5 号 p. 321-324
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe wire processes of high Tc superconducting oxides are studying to realize its application in the field of electric power, however, the critical current density of oxide wire stays in the low range of 102 to 103 A/cm2. In this paper, the two latest results of our studies for fabricating the superconducting oxide to the wire will be presented.抄録全体を表示PDF形式でダウンロード (672K) -
相原 勝蔵, 岡田 道哉, 岡山 昭, 松本 俊美, 松田 臣平1988 年 35 巻 5 号 p. 325-328
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーA tape-shaped wire with YBa2Cu3O7 core and Ag sheath was fabricated by a drawing-rolling method. The critical current density Jc apparentry depended on the thickness of the tape and increased markedly with decreasing tape thickness. The maximum Jc of 3330A/cm2 at 77K in a zero magnetic field was achieved in a tape with 0.06mm thickness. The presence of a 20mT magnetic field reduced the Jc value by 1/100.抄録全体を表示PDF形式でダウンロード (350K) -
池田 靖訓, 大植 康司, 稲葉 和久, 高野 幹夫, 坂東 尚周, 武田 保雄, 菅野 了次, 北口 仁, 高田 潤1988 年 35 巻 5 号 p. 329-332
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe Y2O3-BaO-SrO-CuO system was found to have the superconducting phase Y(Ba1-xSrx)2Cu3Oy where x ranges up to about 1.5. Another new ternary compound Sr3Cu5Oδ was identified. This phase has orthorhombic structure with lattice constants a=3.950Å, b=13.376Å, and c=11.468Å, and solid solution region enclosing Sr3Cu5Oδ, YSr2Cu5Oy, and BaSr2Cu5Oz.抄録全体を表示PDF形式でダウンロード (317K) -
山本 龍也, 古沢 孝幸, 瀬戸 英昭, 朴 慶浩, 桑原 和幸, 長谷川 哲也, 岸尾 光二, 北沢 宏一, 笛木 和雄1988 年 35 巻 5 号 p. 333-338
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーSubmicron-size superconducting powders Ba2YCu3O7-δ(BYCO) having good homogeneity and reactivity were synthesized by an ethanol-aided coprecipitation method by oxalic acid. The obtained ceramics sintered at 1020°C had densities up to 98% of theoretical and exaggerated grain growth was observed at 1000°C and above. A prolonged annealing in flowing oxygen, for as long as 3 weeks, was needed to attain the zero resistivity critical temperature Tc zero=92K for the dense BYCO. A sharp superconducting transition, Tc=0.5K, was then obtained as defined by 10%-90% resistive transition.抄録全体を表示PDF形式でダウンロード (4582K) -
作花 済夫, 幸塚 広光, 梅田 鉄, 門出 孝志, 金 基孫1988 年 35 巻 5 号 p. 339-343
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーSuperconducting YBa2Cu3O7-x fibers and coating films have been prepared using solgel method. Homogeneous viscous sol was prepared by concentrating an aqueous solution of metal acetates. Gel fibers of 5μm - 2 mm in diameter and of more than 50 cm in length could be drawn from the sol. Heat-treated fibers had a hollow structure and were fragile, but showed superconductivity of Tc(end) at 73 K. For preparation of YBa2Cu3O7-x coating films, metal alkoxide solution was prepared using triethanolamine to dissolve copper alkoxide. Repeated application of the solution on a zirconia substrate and heat treatment in O2 resulted in the formation of a superconducting coating film of 1.5 μm in thickness having Tc(end) at 56 K. Factors affecting the properties of the fibers and coating films have been discussed.抄録全体を表示PDF形式でダウンロード (3404K) -
西田 俊彦, 塩野 剛司, 藤岡 秀彰, 西川 友三1988 年 35 巻 5 号 p. 344-348
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーYBa2Cu3Oyセラミック粉末を金属モールド中に封入し,高温で一軸圧縮により短時間で圧縮させた。モールド中で円盤状に焼結したセラミックスについて,圧縮軸に垂直と平行な焼結体断面のX線回折測定を行った結果,結晶の(00Q)の面が圧縮軸と垂直な方向へかなり配向していることが確かめられた。このような配向性焼結体の配向度の表示方法,粒子配向の機構等について若干の考察を加えた。抄録全体を表示PDF形式でダウンロード (4626K) -
武田 保雄, 菅野 了次, 伊奈 一成, 山本 治, 高野 幹夫, 広井 善二, 坂東 尚周1988 年 35 巻 5 号 p. 349-352
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe sintered YBaSrCu3Oy was treated at 300-600°C under high oxygen pressure (PO2=20600atm). The samples showed the decrease of orthorhombic distortion with decreasing the annealing temperature. Below 350°C under 100atm, orthorhombic YBaSrCu3Oy transformed to tetragonal phase with the increase of oxygen content ( y>7.0). The superconductive transition temperature was almost comparable to tho orthorhombic YBaSrCu3Oy.抄録全体を表示PDF形式でダウンロード (493K) -
永田 邦裕, 岩井 孝彦, 清田 達也1988 年 35 巻 5 号 p. 353-357
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーWe have studied that the characteristics of YBa2Cu3Ox superconducting ceramics with hot-pressed in air and oxygen atmosphere was affected by the oxygen diffusion. In the hot-pressed samples in air, since absorbed about 40% oxygen compare that a ordinary sintered methods, it's structure indicated either the tetragonal or the orthorhombic close to tetragonal, besides superconducting did not show until near 77K in spite densification. While the hot-pressed samples in 2-3atm. of oxygen with adding 1-10wt% Ag2O not only indicated the orthorhombic phase but also showed superconducting at 91K regardless of densification, since it was to promote a high oxygen content within material during a sintering process. Therefore we believed that a superconducting and crystal structure of sample was affected by sensitive changes in oxygen content.抄録全体を表示PDF形式でダウンロード (753K) -
真島 一彦, 横田 勝, 永井 宏, 大林 健, 柏屋 俊克1988 年 35 巻 5 号 p. 358-361
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーY Ba 2Cu3Oy powders obtained by pulverizing the mixed powder aggregate fired at 1173K for 86.4ks were cold pressed at 98MPa and sintered at various temperatures for 86.4-1036.8ks, and the relation between the sintering behavior and superconducting properties was investigated.
The abrupt increment of sintered density ratio was observed by the sintering at 1198K after gradual increment with rising sintering temperature up to 1173K, and it remained constant in the higher sintering temperature range than 1198K. Though the sintered density ratio was about 72% even after sintering at 1173K for 1036.8ks, it exceeds 90% in the case of sintering at 1223K for 1036.8ks. The marked degradation of superconducting properties was recognized in the specimen sintered at 1223K for 759.6ks, where the lamella structure along the grain boundary due to the liquid phase formed during sintering was observed.抄録全体を表示PDF形式でダウンロード (926K) -
永田 邦裕, 岩井 孝彦, 岡崎 清1988 年 35 巻 5 号 p. 362-367
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe effects of pore structure on the characteristics of YBa2Cu3Ox superconducting ceramics was investigated. The density of YBa2Cu3Ox ceramics, which is related to pore size and surfaces, was controlled by calcining, milling and sintering condition. The density of samples ranging from 4.80 to 6.17g/cm3 was made by calcining temperature at 900-940°C, dry or wet mill and sintering temperature at 900-1000°C. The resistivity of samples in 300K decreased with increasing density up to 6.00g/cm3, increasing beyond that density and Tc were shift to a low temperature above 6. 00g/cm3. Inversely the critical current density increased with density, but it decreased in case of a magnified densification.抄録全体を表示PDF形式でダウンロード (695K) -
永井 宏, 横田 勝, 真島 一彦, 大林 健1988 年 35 巻 5 号 p. 368-372
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーEffect of Fe substitution for Cu(up to 3at%) on the high temperature phase equilibria of YBa2 Cu3 Oy was investigated under various oxygen partial pressures by electrical conductivity, thermoelectric power measurements and X-ray diffraction. The YBa2 (Cu1-x Fex )3 Oy (x=0-0.03) had orthorhombic structure at room temperature. The electrical conductivity of YBa2 (Cu1-x Fex )3 Oy (x=0-0.03) increased abruptly at about 450°C and the temperature dependence of the resistivity showed a slope change at the temperature which corresponds to the orthorhombic-tetragonal transition. Arrhenius plots of the electrical conductivities of YBa2 (Cu1-x Fex )3 Oy measured under various Po2 consisted of five straight lines. The temperatures at which the straight lines intersected were confirmed to correspond to the phase transition temperatures, which markedly decreased with increasing Fe content(x). The thermoelectric power of YBa2 (Cu1-x Fex )3 Oy (x=0-0.03) is negative across the entire temperature range and Po2 range investigated, which indicates that YBa2 - (Cu1-x Fex )3 Oy (x=0-0.03) is of n-type. The temperature dependence of the thermoelectric power was very similar to that of the electrical resistivity.抄録全体を表示PDF形式でダウンロード (649K) -
松田 元秀, 高田 雅介, 山下 努, 岡本 祥一, 石井 守1988 年 35 巻 5 号 p. 373-378
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe influences of the sintering temperatures in fabricating GdBa2Cu3O7-x ceramics on the critical current densities were investigated. The critical current density measured by the resistive method (Jc, res.) showed a maximum value for the sample sintered at 930°C, while that estimated from the magnetization loop (Jc, mag.) increased monotonically with increase in sintering temperature. The relationship between the decrease in Jc, res. and the second phase at grain boundary was discussed.抄録全体を表示PDF形式でダウンロード (2116K) -
大谷 槻男, 植村 健美, 大熊 和男, 大橋 泰宏, 門田 洋行, 中村 健一1988 年 35 巻 5 号 p. 379-381
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーYBa2(Cu1-xFex)3O7-y (x≥0.03) shows a tetragonal X-ray pattern different from that of well-recognized high-temperature tetragonal phase. Phase transition was observed at around 600°C for all samples (0≤x≤0.05) in magnetic susceptibility, electrical resistivity and thermoelectric power measurements. Seebeck coefficients of the pure YBCO were negative below about 500°C indicating complex conduction mechanism in the compound.抄録全体を表示PDF形式でダウンロード (341K) -
横田 勝, 永井 宏, 真島 一彦, 近藤 二郎, 大林 健1988 年 35 巻 5 号 p. 382-385
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーEffects of La addition substituting for Y in YBa2Cu3Oy on the supercoductivity were investigated. Powder mixtures of Y2O3, BaCO3, La2(CO3)3 and CuO were prepared by mechanical method, cold pressed at the pressure of 98 MPa, sintered at 1253K for 86.4 ks followed by 523K for 86.4ks and then furnace cooled in an oxygen atmosphere.
For estimating the superconductivity, electrical resistivity versus temperature was measured. X-ray diffraction analysis was performed to obtain diffraction patterns and determine lattice constants by using graphite monocromatized CuKα radiation and diffractometer.
Substitution of La for Y in YBa2Cu3Oy did not influence on Tc up to approximately 0.1mol La of Y in YBa2Cu3Oy. However, ΔTc was minimal at approximately 0.1mol La of Y, that is, superconductivity was stabilized by the substitution of La for Y. Over this, Tc inclined to lower with increasing La content. These experimental results may be related to the fact that sintered density of Y0.9La0.1Ba2Cu3Oy became larger than that of YBa2Cu3Oy at the same sintering conditions.
Tcoffset was achieved at 84 K for La0.64Ba2Cu3Oy sample; this is the highest Tc obtained among the LaBaCuO ceramics reported so far.
Lattice parameters of orthorhombic Y1-xLaxBa2Cu3Oy increased monotonously with the increase of La content up to 1 mol La of Y. Orthorhombic single phase was kept to exist up to approximately 0.2 mol of La for Y. Over this, mixture of orthorhombic phase and other phases were confirmed to be coexistent in the specimens.抄録全体を表示PDF形式でダウンロード (3627K) -
長谷 隆司, 梶川 弘, 西村 耕造, 奥田 正彦, 川手 剛雄1988 年 35 巻 5 号 p. 386-391
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe composition of Y-Ba-Cu-O thin films deposited by RF diode sputtering was examined by EPMA (Electron Probe Micro Analysis). The composition of Y-Ba-Cu-O thin films with a target made by the solid state reaction method changed with sputtering time even if the films were deposited under identical conditions. In contrast, the composition of films with a target made by the co-precipitation method were unaffected by sputtering time when they were deposited under identical conditions. Good control of the composition of Y-Ba-Cu-O thin films was achieved by optimizing both the RF input power density and the partial pressure of oxygen.抄録全体を表示PDF形式でダウンロード (998K) -
小林 猛, 斗内 政吉, 吉迫 裕司, 井寄 将博, 藤野 耕三1988 年 35 巻 5 号 p. 392-396
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーFirst attemt has been done in growing epitaxially the heterostructure YBaCuO/ LnBaCuO (Ln=Er, Nd) films. As an extended demonstration of the heterostructure, the superlattice structure was grown. The trilayered perovskite structure, however, was missing in the film (thinner than a few nm) grown on SrTiO3 substrates regardless of their crystal orientation. MgO was a promising material which can solve this problem.抄録全体を表示PDF形式でダウンロード (1312K) -
高田 純, 山本 和貫, 飯島 賢二, 間崎 啓匡, 寺嶋 孝仁, 坂東 尚周1988 年 35 巻 5 号 p. 397-400
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーWe have fabricated quasiparticle tunnel junctions using superconducting single crystal thin film YBa2Cu3O7-x prepared by activated reactive evaporation method. From the tunnel measurement perpendicular to the Cu-O planes at 4.4K gap parameter Δ=11.5±1.5meV and 2Δ/kTc=3.2±0.4 were obtained.抄録全体を表示PDF形式でダウンロード (425K) -
飯田 修一, 光井 俊治, 阿部 清, 松原 直美1988 年 35 巻 5 号 p. 401-404
発行日: 1988/07/25
公開日: 2010/01/15
ジャーナル フリーSince the new frames in physics present a divergenceless mathematical framework for the interaction between the electron fields and the zero-point photon fields, they provide a powerful tool for the analysis of the mechanism of the superconductivity. The minimal coupling effective Hamiltonian predicts that the interaction of a single electron field with a normal-mode of the photon can raise its amplitude by a magnitude of more than 10-7, so that, by the participation of the superconductive electron fields of more than 107 in the number, and, under the action of the proposed possible Q enhancement of the mesoscopic in-crystal resonator, a good possibility is present that a unified complex of the electron fields and the zero-point photon fields is cooperatively created in the specimen. Since this mechanism is spin-independent and has no direct relation to the phonon modes, no isotope effect nor serious effect from the magnetic ions is expected. Different from metals, since the oxides have the ionic lattice which is more rigid and more difficult to be excited by the photon fields, the coupling between the resultant electron-photon field complex and the thermal modes of the phonon fields of the lattice should be much smaller.抄録全体を表示PDF形式でダウンロード (895K) -
池田 靖訓, 大植 康司, 稲葉 和久, 坂東 尚周, 高野 幹夫1988 年 35 巻 5 号 p. 405-408
発行日: 1988/07/25
公開日: 2010/01/15
ジャーナル フリーWe have studied the subsolidus phase relation in the BiO1.5-SrO-CaO-CuO system in air. The compounds were identified by X-ray and electron diffractions. New compounds, Bi7Sr7Cu6Ox, Bi7Sr8Cu5Oy, Bi4Sr8Cu5Oz, Bi0.46CaO0.54-xSrxOy (0.1<x<0.2), Bi3Sr4Ca3Oσ and Bi0.25Sr0.75-xCax, Oy (0≤x<0.2) were found in the system.抄録全体を表示PDF形式でダウンロード (431K) -
内田 孝幸, 伊藤 昌博, 瀧川 貴博, 五味 圭三, 永田 勇二郎1988 年 35 巻 5 号 p. 409-412
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーOptimum composition was determined presisely on new oxide superconductor Bi-Sr-Cu-O system and substitution effects on Bi-Sr-Cu-O and Bi-Sr-Ca-Cu-O system were studied by electric and magnetic measurements. Maximum Tc (onset 10K) was observed at the composition ratio of Bi:Sr:Cu=1:1:1 (designated as BiSrCuOy) in the Bi2O3-SrCO3-CuO ternary system. Transition temperatures were increased with the substitution of light rare earth elements or Ca for Bi or Sr but were decreased with any other substitution. In the case of Bi-Sr-Ca-Cu-O system substitution with Pb, La, Nd, Yb or Lu for Bi or Sr are considered to be valuable for improvement of Tc and for obtaining single phase superconductor.抄録全体を表示PDF形式でダウンロード (526K) -
間崎 啓匡, 池田 靖訓, 高野 幹夫, 坂東 尚周, 小田 喜一, 北口 仁, 高田 潤, 三浦 嘉也1988 年 35 巻 5 号 p. 413-416
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe superconducting properties of Bi-Sr-Ca-Cu-O and Bi-Pb-Sr-Ca-Cu-O systems have been studied in terms of complex susceptibility. It has been revealed that partial substitution of Pb for Bi promotes the production of the high-Tc phase and the superconducting properties of the Bi-system are well improved.抄録全体を表示PDF形式でダウンロード (462K) -
宮本 大樹, 宮本 敬, 稲村 偉, 高橋 弓弦1988 年 35 巻 5 号 p. 417-418
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーEffect of oxygen deficiency of BiSrCaCu2Ox on its superconductivity was studied. The resistance decrease of BiSrCaCu2Ox, fired at 870°C for 16 h, at about 110K increased from 80% to 86%, when the sample is annealed at 850°C in O2 atmosphere. By TG and DTA analysis, a lowering of melting temperature was observed when the sample is heated in Ar atmosphere.抄録全体を表示PDF形式でダウンロード (212K) -
岡 与志男, 山本 直一, 富井 洋一, 北口 仁, 小田 喜一, 高田 潤, 片元 勉, 堀石 七生1988 年 35 巻 5 号 p. 419-423
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe oxalate coprecipitation method was applied to the preparation of a new high-Tc superconductor BiSrCaCu2Ox and crystalline phases obtained by heat treatment were studied in connection with superconducting preperties. The pyrolysis of the coprecipitates was completed below 500°C and subsequent heat treatment above 800°C resulted in the formation of the layered structure characteristic to the superconducting phase. The particle shape was of thin flakes with the size of 10μm. The superconducting phase with Tc of 110K was formed by the heat treatment just below the melting point, which was enhanced in the melt - cooled sample.抄録全体を表示PDF形式でダウンロード (5592K) -
小田 喜一, 北口 仁, 高田 潤, 尾坂 明義, 三浦 嘉也, 池田 靖訓, 高野 幹夫, 坂東 尚周, 山本 直一, 岡 与志男, 冨井 ...1988 年 35 巻 5 号 p. 424-427
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーPartial substitution of Pb for Bi in the Bi-Sr-Ca-Cu-O system has been found to increase sharply the volume fraction of the high-Tc phase when both the starting materials, coprecipitated oxalate being used in the present study, and the heating process are appropriate. The sharp powder X-ray diffraction pattern of the high-Tc phase was obtained from well-grown particles, 1020μm wide and 0.5μm thick typically. The electrical resistance dropped to zero at 107K within the experimental limit of 10-6Ω. A large diamagnetic response in the ac susceptibility due to the Meissner effect was seen below 120K. The fraction of the high-Tc phase over the low-Tc phase was roughly estimated to be 9/1 in volume.抄録全体を表示PDF形式でダウンロード (2051K) -
山路 昭彦, 疋田 真, 日高 義和1988 年 35 巻 5 号 p. 428-431
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーSingle crystals of Bi4(Sr, Ca)6Cu4Oz and Bi4(Sr, Ca)4Cu2Oz were grown from molten Bi2O3-SrCO3-CaCO3-CuO mixtures. These crystals have similar layered structures. The former crystal exibits superconductivity with Tc above 80K and shows Hc2 anisotropy of the ratio of 40-50 between a-b plane and c axis. The latter crystal shows no superconductivity down to 4.2K.抄録全体を表示PDF形式でダウンロード (3259K) -
島川 祐一, 久保 佳実, 真子 隆志, 中林 幸信, 五十嵐 , 佐藤 哲朗1988 年 35 巻 5 号 p. 432-436
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThree samples having general composition Tl2Ba2Can-1Cun04+2n (n=1, 2 and 3) were synthesized, and were examined their electrical properties and crystal structures. Rietveld refinement revealed that as n increased the lattice parameter, a, and interatomic distance Cu-O(2) became shorter, and the Tl-O and Ba-O layers showed a tendency to become flatter. Possible substitution of about 10% of the Ca-site with Tl ion in the 2212 and 2223 phases was also suggested.抄録全体を表示PDF形式でダウンロード (446K) -
上田 寛, 小菅 皓二1988 年 35 巻 5 号 p. 437-441
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーYBa2Cu3Oy with the perfectly ordered Cu1 planes was successfully prepared in the wide composition range of y by slowly cooling in O2 and N2 gases, and the superconductive properties were examined. By "perfect order", one means that the a-sites are empty and the b-sites are fractionally, randomly occupied by oxygen. From resistivity measurement under magnetic fields, the superconductive properties of oxygen deficient YBa2Cu3Oy seem to be composed of two components. The two components may be related to the electronic states of the Cu2 and Cu1 planes.抄録全体を表示PDF形式でダウンロード (606K) -
戸田 広朗, 上田 寛, 小菅 皓二1988 年 35 巻 5 号 p. 442-445
発行日: 1988/07/25
公開日: 2010/01/15
ジャーナル フリーThe SmxBa1-xCuOy system has been investigated by powder X-ray diffraction, electrical resistivity (R) and thermogravimetric analysis (TGA) measurements. This system forms a solid solution in the composition range 0.33≤x≤0.50. With increasing x, this system undergoes a phase transition from the orthorhombic to tetragonal structure around x≅0.41. The temperature dependence of R shows two step drops (Tc1, Tc2) toward zero resistivity on cooling, which behavior is very similar to the one observed in YBa2Cu3Oy. Tc2 gradually decreases through the orthorhombic to tetragona phase.抄録全体を表示PDF形式でダウンロード (474K) -
吉武 務, 久保 佳実, 五十嵐 等, 佐藤 哲朗1988 年 35 巻 5 号 p. 446-449
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThin films of Bi-Sr-Ca-Cu-O system were prepared on (100)MgO substrate by coevaporation of Bi2O3, Sr-Ca alloy and Cu metal. The films with relatively high Ca composition showed a superconducting transition with zero resistance Tc of 107K after annealed at 890°C for 5 hours. High Ca composition, high annealing temperature and long annealing duration were necessary to prepare the films with zero resistance Tc over 100K. These films showed large anisotropy of the upper critical field.抄録全体を表示PDF形式でダウンロード (484K) -
岩井 裕, 前田 孝雄, 石井 守, 高田 雅介, 山下 努1988 年 35 巻 5 号 p. 453-456
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーThe superconductive properties of the (1-x)YBa2Cu3O7-y - xTbBa2Cu3Oz system were studied. The structures are orthorhombic and lattice parameters are independent on the concentration of Tb for x<0.50. The transition from orthorhombic to tetragonal occurs for x>0.50. Critical temperatures are higher than 90K for x<0.50 and decrease for x>0.50, and superconductivity desappears at x=0.75.抄録全体を表示PDF形式でダウンロード (383K) -
核磁気共鳴法による安岡 弘志1988 年 35 巻 5 号 p. 457-464
発行日: 1988/07/25
公開日: 2009/05/29
ジャーナル フリーPDF形式でダウンロード (1125K)
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