巻号一覧
40 巻, 2 号
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小菅 皓二1993 年 40 巻 2 号 p. 130
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (77K) -
山根 久典, 宮崎 譲, 平井 敏雄1993 年 40 巻 2 号 p. 131-136
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーStudies of newly discovered cuprates and cuprate superconductors containing carbonate groups were reviewed. Carbonate groups (CO3), CuOx and alkali-earth elements (Sr, Ba) comprised new block layers of [(Sr, Ba)2(C, Cu)Ox]. Combination of the block layers containing CO3 and previously known block layers (oxygen-deficient metal layers or fluorite layers) brought new compounds and superconductors. Superconducting transition temperatures of (Sr1-xBax)2Cu1+yO2+2y+d(CO3)1-y' (Y0.5Ca0.5)0.95 Sr2.05Cu2.4Ox(CO3)0.6 and (Y0.73Ce0.27)2Sr2Cu2.65Ox(CO3)0.35 were around 40, 68 and 17 K, respectively.抄録全体を表示PDF形式でダウンロード (313K) -
垣花 眞人, 八島 正知, 吉村 昌弘, 間崎 啓匡, 安岡 宏1993 年 40 巻 2 号 p. 137-145
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーA novel "polymerized complex" technique to produce highly pure copper based high-Tc superconductors has been developped. The method is based on the formation of a plymer metal complex precursor which is prepared through polyesterification between metal citrate complexes and ethyleneglucol. The general idea of this technique is to have a polymer complex with various metal ions, which are uniformly distributed in the polymer network keeping the initial stoichiometric ratio. Heating of the polymer metal complex precursor at high temperature brings about a breakdown of the polymer, which may allow to construct lattices of ceramics oxides directly. It is then assumed in this study that low cation mobility in the highly viscous polymer network causes only little segregation of the various metal ions during the pyrolysis. A particular attention was paid on the phase purity of the product, and the single-phase character of the final product was confirmed by the combined results of X-ray diffraction, Raman scattering and complex magnetic susceptibility measurements.. The present paper highlights the advantages of the polymerized complex technique in the synthesis of copper-based ceramic superconductors. Emphasis is placed to outstanding purity of the product as is revealed by superconducting transition widths much sharper than those for ceramic samples previously reported synthesis procedures.抄録全体を表示PDF形式でダウンロード (578K) -
武田 保雄, 冨田 英也, 向井 保雄, 今西 誠之, 山本 治, 東 正樹, 高野 幹夫1993 年 40 巻 2 号 p. 146-150
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーTwo kinds of methods were carried out in order to dope the oxygen in La2CuO4 crystals; the annealing under high oxygen pressure at high temperature and the electrochemical oxidation in an aqueous alkaline solution at ambient temperature. The difference in the orthorhombicity was seen in La2CuO4+z with the same z value, prepared by different routs, which indicates the different excess oxygen distribution. The electrochemical oxidation is also effective to bring the superconductivity in La2-xBixCuO4+z and La2-xPbxCuO4+z. Some samples show the Tc on set of 30K for Bi doped system and 15-20K for Pb doped one.抄録全体を表示PDF形式でダウンロード (266K) -
勝山 茂, 泉田 寛, 真島 一彦, 永井 宏1993 年 40 巻 2 号 p. 151-155
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーThe substitution for the Ba sites in Sm1/3Ba2/3CuOy (=SmBa2Cu3Oy) by Sm induces the local oxygen disordering in the Cul-O planes since the Sm atoms located on the Ba sites are apt to have eight oxygen coordination. In order to investigate the effectiveness of the disordered oxygens as pinning centers for flux lines in SmxBa1-xCuOy, the magnetic hysteresis curves were examined by SQUID magnetometer. As a result, the critical current density Jc, which is estimated from the magnetic hysteresis curves, decreased with increase of degree of the oxygen disordering in the Cul-O planes of SmxBa1-xCuOy. Thus, the disordered oxygens do not act as effective pinning centers. This result is in contrast to the result in YBa2(Cu1-xFex)3Oy system where the Jc has the maximum value at about x=0.02, and indicates that the increase of Jc in the YBa2(Cu1-xFex)3Oy system is ascribed not to the disordering oxygens, but to the clustered Fe atoms.抄録全体を表示PDF形式でダウンロード (256K) -
垣花 眞人, 八島 正知, 吉村 昌弘, 間崎 啓匡, 安岡 宏1993 年 40 巻 2 号 p. 156-160
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーSuperconducting YBa2-xSrxCu4Oy [(Sr/Ba)-124] ceramics with x=0.0, 0.2, 0.4 and 0.6 have been synthesized by a combined process of the polymerized complex method and high oxygen pressure technique. Substitution of larger Ba ions by smaller Sr ions induces compression of lattices, which reflects decrease in lattice parameters, a, b, and c, with increasing Sr content x. Complex magnetic susceptibility measurements have revealed pure samples of (Sr/Ba)-124 with onsets of the superconducting transitions at 81.3 - 81.8 K and with their transition widths ΔTc (10-90%) = 2 - 3.5 K. Of particular interest is the invariance of Tc(onset) by Sr-doping in 124 in marked contrast with the corresponding 123 system where Tc(onset) is monotonically decreasing with increasing Sr content at a rate of about 2 K/(10% Sr). Raman spectroscopic measurements have shown that the vibrational mode for the apex oxygen, O(4), does not shift at all with increasing Sr content. This suggests that the charge balance between the CuO2 plane and the CuO double chain remains almost unchanged, which may in turn predict a constant Tc in the (Sr/Ba)-124 system as was indeed observed in this study.抄録全体を表示PDF形式でダウンロード (313K) -
Tatsuya Yamamoto, Lourdes Salamanca-Riba, Maria Foldeaki, Robert C. O' ...1993 年 40 巻 2 号 p. 161-165
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーStrongly textured high Tc bulk YBCO was prepared with rapid solidification (RS) and directional annealing (DA) processes. It was found that the 123 crystallites grow with their c-axes perpendicular to the sample traveling direction. We have obtained transport Jc of 2, 000 A/cm2 by pulse current and 1.150A/cm2 by dc current at 77K in a 15T field. It has been found that the Jc values measured by pulse and dc methods are essentially equal in high magnetic fields (8T to 15T) and Jc measured by pulse current is larger than that measured by dc current in magnetic fields below 8T.
Flux creep rate was same for field-cooled(fc) or zero field-cooled (zfc) conditions. This indicates that flux does not easily penetrate the sample along non-superconducting grain boundaries. The orientation-dependent shape of the dc magnetic hysteresis loops proved the anisotropic nature of the flux line structure and the flux pinning.
Dislocations with a density of-5x109/cm2 were found in the 123 crystals and they were found to lie on the a-b plane.
The enhancement of Jc is probably due to flux pinning by the dislocations, the preferred orientation of the crystallites with the a-b plane parallel to the sample traveling direction and the strong grain couplings.抄録全体を表示PDF形式でダウンロード (1398K) -
間崎 啓匡, 安岡 宏, 垣花 眞人, 吉村 昌弘1993 年 40 巻 2 号 p. 166-170
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーWe have investigated harmonic ac susceptibilities Xn=Xn'-iXn" (n=1, 2, 3) of a ceramic superconductor HoBa2Cu4Oy synthesized by the polymerized complex method. The sample are immersed in an external field H(t)= Hdc+ Haccos(ωt), where Hdc (≥0) is a dc bias field and Hac (>0) is an ac field amplitude. Measurements of Xn were carried out for μOHac = 0.01-0.1 mT and the fundamental frequency was 132 Hz. The observed results were analyzed within the construct of the Kim-Anderson model for critical current density and were compared to those previously obtained for other sintered ceramic superconductors. Details of the measurement and the analysis are presented.抄録全体を表示PDF形式でダウンロード (290K) -
大藤 善弘, 志村 健一, 寺嶋 孝仁, 坂東 尚周, 矢野 義彦1993 年 40 巻 2 号 p. 171-174
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーWe have examined microstructures of the growth interface in ultrathin YBa2Cu3O7 (YBCO) films grown on (100) SrTiO3 and (100) MgO substrates. On both substrates YBCO films are completely c-axis oriented, and the surface is flat within ±one unit cell thickness. On the SrTiO3 substrare the atomic stacking sequence is usually SrO-TiO2-BaO-CuO2-Y-CuO2 BaO-CuO. In contrast, on the MgO substrate various sequences appear, because there are many narrow steps on the substrate. On both substrates the influence of steps tends to disappear as the film grows up to two unit cell thickness. The surface structure of YBCO was the same on both substrates: the film is always terminated by the BaO-CuO2-Y-CuO2-BaO-CuO sequence.抄録全体を表示PDF形式でダウンロード (4636K) -
吉川 信一, 鄂 剛, 加藤 奈美江, 金丸 文一1993 年 40 巻 2 号 p. 175-178
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーHigh pressure synthesized infinite-layered superconductor Sr0.9La0.1CuO2 showed very large magnetic hysteresis. Its critical current value of 1010A/m2 at 4.2K was obtained applying Bean's model. A.C. measurement also showed similar value as its intra-grain Jc value. CaCuO2 and (Ca1-xNax)CuO2 could be obtained applying sol-gel method using acetates. Infinite-layered (Ca1-ySry)CuO2 was also prepared firing the precipitate from acetates in ambient atmosphere. The solid solution range was estimated to be upto around y=0.15.抄録全体を表示PDF形式でダウンロード (200K) -
東 正樹, 池田 成明, 広井 善二, 高野 幹夫, 坂東 尚周, 大高 理, 山中 高光, 武田 保雄1993 年 40 巻 2 号 p. 179-182
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーHigh quality samples of both the alkaline-earth deficient type and the rare-earth substituted type of infinite-layered superconductors have been synthesized using a cubic anvil high-pressure apparatus. The result of oxygen content analysis by means of iodometry strongly supports the assertion that the A cation deficient phase can be either a p-type or an n-type superconductor, while the rare-earth substituted ones are n-type.抄録全体を表示PDF形式でダウンロード (218K) -
池田 靖訓, 大藤 善弘, 高野 幹夫, 坂東 尚周, 新苗 稔展, 高田 潤1993 年 40 巻 2 号 p. 183-186
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーMechanical grinding and the reformation from ground powder of the Bi-2201 phase were examined by XRD, TEM and DTA. The "2201" phase changed easily into amorphous powder and ultra-fine crystals by mechanical grinding. When heated above 800°C, the ground powder reacted to reform the original "2201" phase. The fine "2201" crystals smaller than a critical size remaining in the ground powder were decomposed into Bi2CuO4 and SrCO3 by heating around 500°C in air, while even at room temperature in the air the XRD peaks from these ultra-fine crystals tend to disappear and SrCO3 formed on grinding.抄録全体を表示PDF形式でダウンロード (1851K) -
機械的粉砕した非晶質粉からの高温相の生成草野 圭弘, 新苗 稔展, 難波 徳郎, 高田 潤, 池田 靖訓, 高野 幹夫1993 年 40 巻 2 号 p. 187-190
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーChemical and mechanical stability of the high-Tc phase in the Bi-Pb-Sr-Ca-Cu-O system has been studied. In particular, the formation of the high-Tc phase has been discussed for samples of the amorphous powder with a composition of Bi0.9Ph0.2Sr1.0Ca1.0Cu1.6Oz prepared by mechanical grinding. Annealing of the amorphous powder at low temperatures(500-800°C) leads to precipitation of some impurity phases. The Pb-rich low-Tc phase with an orthorhombic structure symmetry was found to form in samples of the amorphous powder heated at 820°C in air. The formation of the Pb-rich low-Tc phase seems to suppress the formation of the high-Tc phase in subsequent heat treatments at 850°C. Almost monophasic products of the high-Tc phase were obtained when the amorphous powder was heated at 840°C for 48h and subsequently at 850°C for 96h after calcination at 720°C.抄録全体を表示PDF形式でダウンロード (1347K) -
真島 一彦, 長谷川 伸二, 勝山 茂, 永井 宏1993 年 40 巻 2 号 p. 191-195
発行日: 1993/02/15
公開日: 2009/12/04
ジャーナル フリーThe high temperature electrical resistivity and superconducting properies of Bi-Sr-Ca-Cu-O samples heat-treated in H2 gas were investigated. The results are summarized as follows:
(1)It was recognized that the measurement of Tc for the Bi2Sr2CaCu2Oy(2212) samples heat-treated at above 473K was impossible because of the great reduction by hydrogen treatment.
(2)With increasing H2 gas pressure during heat treatment at 423K, Tc for the 2212 sample increased, whereas that for the 2223 samples decreased. In this case, the increment of H content was recognized on both of these two kinds of samples. On the other hand, the oxygen content decreased slightly with increasing H2 gas pressure.
(3)Though the increment of H content was observed on the 2212 specimen heat-treated at as low temperature as 373K for longer period than 48h under H2 gas pressure of 25atm, the reduction phenomena was hardly recognized.抄録全体を表示PDF形式でダウンロード (251K) -
遠藤 加寿代, 草野 圭弘, 難波 徳郎, 高田 潤1993 年 40 巻 2 号 p. 196-199
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーThe effect of Li addition to the low-Tc phase in Bi-Sr-Ca-Cu-O system has been studied for the samples with nominal compositions of Bi:Sr:Ca:Cu:Li=2:3-y:y:2:x(x=0 to 0.6, y=1.25, 1.5, 2.0) heated at 600 to 760°C for 12 to 48h in air. The Li addition promotes the formation of the low-Tc phase. Monophasic samples of the low-Tc phase were obtained for x=0.2 to 0.6 by heating at remarkably lower temperatures. The lattice constant c of the low-Tc phase depends on y as well as Li content. As the heating time extends, the Li content in the low-Tc phase decreases. For y=1.25 and 1.5 c increases as the Li content increases. On the contrary, c for y=2.0 decreases as the Li content increases.抄録全体を表示PDF形式でダウンロード (239K) -
小林 斉也, 福原 実, 土井 章, 高田 利夫, 草野 圭弘, 高田 潤, 池田 靖訓, 高野 幹夫1993 年 40 巻 2 号 p. 200-203
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーSamples with compositions of Bi:Pb:(Sr, Ba):Ca:Cu=0.9:0.2:(1.0-x, x):1.0:1.6, in which O≤x≤0.07, were prepared by heating at 844°C in air after heating at 828°C in air or at 787°C in Ar.The Pb-free(or poor)low-Tc phase with a tetragonal structure was formed by heating at 828°C in air, while the heat treatment at 787°C in Ar led to formation of the Pb-rich low-Tc phase with anorthorhombic structure. The lattice parameter c of these low-Tc phases increases as x increases, resulting from the Ba substitution for Sr. By the final heating in air, the high-Tc phase formsthrough the Pb-rich low-Tc phase as well as the Pb-poor one. Ba substitution promotes theformation of the high-Tc phase and elongates its c-axis length.抄録全体を表示PDF形式でダウンロード (244K) -
高田 潤, 藤阪 孝誠, 細谷 勝宣, 江木 俊雄, 草野 圭弘, 難波 徳郎, 池田 靖訓, 高野 幹夫1993 年 40 巻 2 号 p. 204-207
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーChemical and mechanical stability of the Ba-added high-Tc phase has been studied using XRD and DTA for samples of Bi0.9Pb0.2Sr1.0BaxCa1.0Cu1.6Oz with x=0 and 0.05. Some impurities were observed in all samples after the heat treatment at 300-820°C. BaPb0.75Bi0.25O3 was also formed in the Ba-added samples heated at 700-800°C. These impurities were thought to be formed from the amorphous phase which was produced by mechanical grinding of the high-Tc phase. The impurities disappeared and an almost monophasic sample of the high-Tc phase was obtained by heating at 850°C. The lattice parameter c of the Ba-added high-Tc phase was longer than that of the Ba-free one above 800°C. The parameter c of the Ba-added sample heated at 850°C increased with an increase of heating time and was saturated over 48h. The increase of c was due to the Ba dissolution in the high-Tc phase.抄録全体を表示PDF形式でダウンロード (222K) -
堀田 勝喜, 鈴木 敏正, 廣瀬 治男, 船戸 健一1993 年 40 巻 2 号 p. 208-211
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーAg coated powders of oxide superconductor Bisystem prepared by the solid phase reaction method were sintered after pressing. The electrical resistance versus temperature, the critical current density, X-ray diffraction and SEM images were measured on these materials. Although the resultant critical current density is increased, the electrical resistance versus temperature characteristic changed slightly with the amount of sputtered Ag coat.抄録全体を表示PDF形式でダウンロード (1903K) -
江木 俊雄, 渋谷 和幸, 林 征治, 小川 陸郎, 川手 剛雄, 細谷 勝宣, 高田 潤1993 年 40 巻 2 号 p. 212-215
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーThe effects of Ba-doping on the critical current density (Jc) of Ag-sheathed tapes of (Bi, Pb)-Sr-Ca-Cu-O superconductors were studied for samples with nominal compositions of Bi1.8Pb0.4 Sr2.0-xBaxCa2.2Cu3.0Oz (x=O to 0.6). The Jc increased with a small amount of Ba-doping, while it decreased with a large amount of Ba-doping. The maximum value of the Jc was 17, 400 A/cm2 at 77K in OT for x=0.1. Ba-doping improved the Tc value of the tape, resulting from the dissolution of Ba into the Bi2223 phase. The Jc increase with Ba-doping was due to the increase of the ratio of Bi2223 phase and the decrease of the size and quantity of impurity phases.抄録全体を表示PDF形式でダウンロード (1633K) -
江木 俊雄, 細谷 勝宣, 難波 徳郎, 高田 潤1993 年 40 巻 2 号 p. 216-219
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーThe formation of the high-Tc phase in the Bi-Pb-Sr-Ca-Cu-O system has been studied in ground powder samples enclosed in silver pipes.The samples with a composition of Bi:Pb:Sr:Ca:Cu=0.9:0.2:1.0:1.0:1.6 prepared by heating at 850°C for 24h were mechanically ground for various periods, put into silver pipes and heated at 840-850°C.The formation of the high-Tc phase was found to be promoted in the samples enclosed in the silver pipes, depending upon three factors: grinding time, atmosphere in the pipe and reaction between the powder sample and the silver pipe.抄録全体を表示PDF形式でダウンロード (273K) -
香山 滉一郎, 原田 智裕1993 年 40 巻 2 号 p. 223-227
発行日: 1993/02/15
公開日: 2009/12/04
ジャーナル フリーThe standard Gibbs free energies for the formation of FeWO4 and Fe2WO6 were determined in the temperature range from 1123K to 1273K by measuring electromotive forces of galvanic cells having a solid oxide electrolyte. The results obtained are as follows:
(1) ΔtG ?? (FeWO4)=-1184300+357. 6T±200 J/mol
ΔtG ?? (FeWO4)=-1184300+357.4T±200 J/mol
(2) ΔtG ?? (Fe2WO6) =- 1651900+516. 1 T ±300 J/mol
ΔtG ?? (Fe2WO6)=-1651900+515.8T±300 J/mol,
where the superscript ?? denotes that the standard pressure is 1 bar(100, 000 Pa) whereas ?? denotes 1 atm(101, 325 Pa).抄録全体を表示PDF形式でダウンロード (291K) -
辻本 真司, 中野 修, 永野 光芳1993 年 40 巻 2 号 p. 228-231
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーIn this paper, we report mechanical properties of ZrO2-MgO substrate for thin film magnetic head. Two mechanical properties were measured. One is the tribological property and the other is the slicing resistance. In the tribological property test(so-called "Shoe-Shine Test"), the ZrO2-MgO material showed good result compared with the current material (Al2O3-TiC), and also gave no damages against the magnetic media.
On the other hand, the slicing resistance for ZrO2-MgO substrate with less than 84% MgO content was higher two times than for the current material. The sample containing more than 90% MgO, however, showed the same slicing resistance as for the current material. These phenomena were accommodated by the distribution of ZrO2 grains, so that, the low slicing resistance was thought to be due to the separation of each ZrO2 grain. This was also confirmed by measuring the thermal conductivity.抄録全体を表示PDF形式でダウンロード (2116K) -
佐々木 卓也1993 年 40 巻 2 号 p. 232-235
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーA thermal treatment causes occasionally some defects for green body like cracks or blisters in a binder removal stage of the ceramic injection molding process.
A debinding mechanism by heating for the injection molded alumina contained the EVA and Wax is investigated in this study. By means of observations of a cross section of the alumina compact in the heating process, it has been found that the brown layer, formed at the surface, advances into the compact during the process. The non-degraded binder as a white region has been also observed inside of the layer.
The surface layer is postulated as a kind of reactant in the heating process. From the result of the analysis of kinetics for the reaction system, the rate determining step will be proposed for a reaction at the interface between the brown surface layer and the white inner region.抄録全体を表示PDF形式でダウンロード (3170K) -
多田 吉宏, 佐藤 悌介1993 年 40 巻 2 号 p. 236-240
発行日: 1993/02/15
公開日: 2009/05/22
ジャーナル フリーSynthesis and consolidation of an iron-aluminide, Fe3Al, via powder metallurgical route has been studied. A mixture of elemental powders of iron (75at%) and aluminum (25at%) is charged into a vibratory ball mill and milled for eighty hours. X-ray diffraction shows that the mechanically alloyed powder consists of crystalline iron and non-crystalline aluminides and that it changes into a single phase of Fe3Al during following hot consolidation processes. To otain fully dense Fe3Al compacts, several hot consolidation techniques, including uniaxial hot compaction, hot upsetting, hot pressing, hot extrusion and hot isostatic pressing, are examined. Among these processes, HIP is the most superior consolidation technique to obtain products with full density and good mechanical properties. Although uniaxial hot consolidation and hot upsetting are not suitable for higher densification, substantial densification is achieved in hot pressing and hot extrusion; for example, the density of 95-97% of the theoretical value is obtained by extruding compacts at temperatures above 1150°C. Addition of 5wt% of aluminum oxide particle brings increases in hardness and 0.2% proof stress without any loss of ductility.抄録全体を表示PDF形式でダウンロード (296K) -
馬越 幹男, 伊藤 普, 中村 良三, 横山 藤平, 浦山 清, 加藤 正史1993 年 40 巻 2 号 p. 241-246
発行日: 1993/02/15
公開日: 2009/12/04
ジャーナル フリーThe Ni-55%Al and -20%Al composite powders were prepared by the mechanofusion process and were plasma sprayed on mild steel substrates in air. The properties of the powders and the sprayed coatings were examined, and were compared with those of several commercial powders and their coatings. The fine Al particles adhered well to the Ni core particles, but did not homogeneously coat them while mhanofusing. The mechanofused powders were found to differ from the commercial products regarding morphology and microstructure. The intermetallic compounds were not formed in the coatings in any case of air plasma spraying because of partial oxidation of the components in the powders and short reaction time for forming aluminides. The microstructure, hardness, adhesion strength and abrasive wear resistance of the coatings, which were plasma sprayed with the mechanofused powders, were almost the same as those of the coatings obtained by using the commercial powders.抄録全体を表示PDF形式でダウンロード (2834K)
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