{"title":"Key issues for the characterization of RE–Ba–Cu–O systems (RE: Nd, Sm, Eu, Gd)","authors":"M Murakami","doi":"10.1016/S0964-1807(98)00087-8","DOIUrl":"10.1016/S0964-1807(98)00087-8","url":null,"abstract":"","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"6 2","pages":"Pages 51-59"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0964-1807(98)00087-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90965075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"OCMG process for filamentary Nd123 superconductor produced by solution spinning","authors":"Tomoko Goto, Masahide Takahama, Takuji Kimura","doi":"10.1016/S0964-1807(98)00096-9","DOIUrl":"10.1016/S0964-1807(98)00096-9","url":null,"abstract":"<div><p><span>The oxygen controlled melt growth (OCMG) process for filamentary Nd123 superconductors has been studied to enhance the </span><em>J</em><sub>c</sub> values. The filamentary Nd<sub>1.18</sub>Ba<sub>2.12</sub>Cu<sub>3.09</sub>O<sub><em>x</em></sub> (1) and Nd<sub>1.25</sub>Ba<sub>2.05</sub>Cu<sub>3.10</sub>O<sub><em>x</em></sub> (2) precursors were prepared by dry spinning through a homogeneous aqueous solution containing mixed acetates of Nd, Ba and Cu, poly(vinyl alcohol). The calcined filaments were partially melted in flowing 0.1% O<sub>2</sub>+Ar. The <em>T</em><sub>c</sub> values of filament (1) was 94.5<!--> <!-->K and 88.5<!--> <!-->K for filament (2). By controlling the heating condition, maximum <em>J</em><sub>c</sub> values of 2.4×10<sup>4</sup> A/cm<sup>2</sup> and 1.8×10<sup>4</sup> A/cm<sup>2</sup> at 77<!--> <!-->K and 0<!--> <!-->T were attained for filaments (1) and (2), respectively. A window of the optimum heating conditions for filament (2) was narrow and the reproducibility of the high <em>J</em><sub>c</sub> value was poor.</p></div>","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"6 2","pages":"Pages 157-162"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0964-1807(98)00096-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90202083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Nd4Ba2Cu2O10 addition on the pinning properties of Nd-Ba-Cu-O crystals","authors":"T. Mochida, N. Chikumoto, M. Murakami","doi":"10.1016/S0964-1807(98)00104-5","DOIUrl":"https://doi.org/10.1016/S0964-1807(98)00104-5","url":null,"abstract":"<div><p>We have studied the effects of Nd<sub>4</sub>Ba<sub>2</sub>Cu<sub>2</sub>O<sub>10</sub> (Nd422) on the pinning characteristics of NdBa<sub>2</sub>Cu<sub>3</sub>O<sub>7−<em>δ</em></sub> (Nd123) crystals. Like Y<sub>2</sub>BaCuO<sub>5</sub> particles in the Y–Ba–Cu–O system, the addition of Nd422 could enhance critical current density <em>J</em><sub>c</sub> at lower fields. The peak field (<em>B</em><sub>pk</sub>) and the <em>J</em><sub>c</sub> value at <em>B</em><sub>pk</sub> were almost independent of Nd422 contents although a slight decrease in <em>J</em><sub>c</sub> at <em>B</em><sub>pk</sub> was observed with increasing Nd422 contents. The normalized relaxation rate (<em>S</em>) increased for all the samples when the field exceeded <em>B</em><sub>pk</sub>. The addition of Nd422 was effective in preventing a rapid increase in <em>S</em> above <em>B</em><sub>pk</sub>. The exponent <em>μ</em>, defined in the collective creep model, was deduced by fitting the experimental data and was found to show strong field dependence. We found that <em>μ</em> changes from positive to negative at around <em>B</em><sub>pk</sub><span>, suggesting that the flux creep mechanism is different below and above </span><em>B</em><sub>pk</sub>.</p></div>","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"6 2","pages":"Pages 217-224"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0964-1807(98)00104-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91636906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Provoost, K. Rosseel, D. Dierickx, R. Silverans, V. Moshchalkov, H. Kojo, M. Murakami
{"title":"Stress analysis in melt processed RBa2Cu3O7 (R = Y, Nd) by micro-raman spectroscopy","authors":"R. Provoost, K. Rosseel, D. Dierickx, R. Silverans, V. Moshchalkov, H. Kojo, M. Murakami","doi":"10.1016/S0964-1807(98)00100-8","DOIUrl":"https://doi.org/10.1016/S0964-1807(98)00100-8","url":null,"abstract":"","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"5 1","pages":"185-192"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78429994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P Badica , G Aldica , V.V Morozov , S Popa , S Mandache
{"title":"The influence of sintering environment and intermediate grounding on the scattering of the superconducting characteristics in BSCCO ceramic produced by spray-frozen, freeze drying method","authors":"P Badica , G Aldica , V.V Morozov , S Popa , S Mandache","doi":"10.1016/S0964-1807(97)00040-9","DOIUrl":"https://doi.org/10.1016/S0964-1807(97)00040-9","url":null,"abstract":"<div><p><span>The effect of intermediate grounding and sintering environment (air or sintered powder) on the superconducting characteristics of Bi(Pb)-Sr-Ca-Cu-O bulk ceramics obtained by spray-frozen freeze drying technique was investigated by X-ray diffraction, electric and magnetic measurements. Intermediate grounding leads to higher scattering coefficients of the superconducting characteristics. This result does not depend on sintering environment. Improved results are obtained when sintering is performed by immersing pellets “in powder” rather than placing them “on powder”. The powder used as sintering environment was pyrolized precursor powder calcinated in air for 100</span> <!-->h.</p></div>","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"4 12","pages":"Pages 583-589"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0964-1807(97)00040-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91760106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Wen, T. Usagawa, H. Zama, Y. Enomoto, T. Morishita, N. Koshizuka
{"title":"Microstructures of RE(RE:Y,Pr)Ba2Cu3Oy films grown on (001), (100) and (110) oriented YBa2Cu3Oy single crystal substrates","authors":"J. Wen, T. Usagawa, H. Zama, Y. Enomoto, T. Morishita, N. Koshizuka","doi":"10.1016/S0964-1807(98)00102-1","DOIUrl":"https://doi.org/10.1016/S0964-1807(98)00102-1","url":null,"abstract":"","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"4 1","pages":"199-206"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89674351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X. Yao, E. Goodilin, Y. Yamada, H. Sato, Y. Shiohara
{"title":"Crystal growth and superconductivity of Y1−xNdxBa2Cu3O7−δ solid solutions","authors":"X. Yao, E. Goodilin, Y. Yamada, H. Sato, Y. Shiohara","doi":"10.1016/S0964-1807(98)00099-4","DOIUrl":"https://doi.org/10.1016/S0964-1807(98)00099-4","url":null,"abstract":"<div><p>Single crystals of Y<sub>1−<em>x</em></sub>Nd<sub><em>x</em></sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7−<em>δ</em></sub> [Y(Nd)BCO] solid solutions, in which the Nd content <em>x</em> ranged from 0.098 to 0.410, were grown by the crystal pulling method. The Nd substitution content <em>x</em> in the crystal can be controlled with the processing temperature. With an increase of the processing temperature, the Nd concentration in the liquid increased, and accordingly, resulted in the higher Nd substitution content in single crystals. When <em>x</em>=0.410, the ratio of Nd+Y to Ba in single crystals became high and the <em>T</em><sub>c</sub> was depressed, indicating evidence of the Nd substitution at Ba sites. The critical temperature <em>T</em><sub>c</sub> of 89±2<!--> <!-->K was obtained from oxygenated Y<sub>1−<em>x</em></sub>Nd<sub><em>x</em></sub> Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7−<em>δ</em></sub> single crystals at 340°C for 200<!--> <!-->h and could be enhanced up to 91<!--> <!-->K by annealing at 500°C for 3 days. For all Y(Nd)BCO solid solutions, even a small amount of Nd content (<em>x</em>=0.098), the second peaks appear in the range of 1.2–1.7<!--> <!-->T for the applied field <em>H</em> parallel to the <em>c</em>-axis of samples in the <em>M</em>–<em>H</em> loops, which may be due to a double substitution of both Y<sup>3+</sup> and Ba<sup>2+</sup> by Nd<sup>3+</sup><span>. X-ray measurements of the lattice parameter proved the above double substitution.</span></p></div>","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"6 2","pages":"Pages 175-183"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0964-1807(98)00099-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90002729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Das A , S. Koishikawa , T. Fukuzaki , M. Muralidhar , M. Murakami
{"title":"Magneto-optical characterization of Nd0.33Eu0.33Gd0.33Ba2Cu3O7 superconductors","authors":"Das A , S. Koishikawa , T. Fukuzaki , M. Muralidhar , M. Murakami","doi":"10.1016/S0964-1807(98)00101-X","DOIUrl":"https://doi.org/10.1016/S0964-1807(98)00101-X","url":null,"abstract":"<div><p><span>We have studied the flux penetration and trapping behavior of Nd</span><sub>0.33</sub>Eu<sub>0.33</sub>Gd<sub>0.33</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub><span> superconductors melt-processed in a reduced oxygen atmosphere with magneto-optical techniques. It was found that the critical state is well established in the whole sample, showing that the sample is a single grain without weak links. Critical current densities estimated from magneto-optical observations were in good agreement with the values obtained from magnetization measurements.</span></p></div>","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"6 2","pages":"Pages 193-198"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0964-1807(98)00101-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91636908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Solubility limits of LRE1+xBa2−xCu3O7+δ","authors":"H. Wu , K.W. Dennis , M.J. Kramer , R.W. McCallum","doi":"10.1016/S0964-1807(98)00090-8","DOIUrl":"10.1016/S0964-1807(98)00090-8","url":null,"abstract":"<div><p>Unlike YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7+<em>δ</em></sub><span> which forms only a stoichiometric compound, the light rare earth (LRE) elements form a solid solution of LRE</span><sub>1+<em>x</em></sub>Ba<sub>2−<em>x</em></sub>Cu<sub>3</sub>O<sub>7+<em>δ</em></sub> (LRE123ss) with increasing substitution of the rare earth for Ba<sup>2+</sup><span><span> as the ionic radii of the rare earth increases. The effects of </span>oxygen partial pressure (Po</span><sub>2</sub><span>) on the solubility limits of LRE123ss (LRE=Pr, Nd, Sm, Eu, and Gd) were studied by differential thermal analysis, X-ray diffraction and measurement of superconducting transition temperature (</span><em>T</em><sub>c</sub>). An understanding the Po<sub>2</sub> and temperature dependence of the solubility limits will not only provide guidelines for obtaining high <em>T</em><sub>c</sub><span> in LRE123ss but also clarify the flux pinning mechanism in these systems.</span></p></div>","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"6 2","pages":"Pages 87-107"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0964-1807(98)00090-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77950161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T Puig, B Martı́nez, R Yu, A Hu, V Gomis, F Sandiumenge, X Obradors
{"title":"Critical currents in air processed NdBa2Cu3O7 melt-textured superconductors","authors":"T Puig, B Martı́nez, R Yu, A Hu, V Gomis, F Sandiumenge, X Obradors","doi":"10.1016/S0964-1807(98)00092-1","DOIUrl":"10.1016/S0964-1807(98)00092-1","url":null,"abstract":"<div><p>Single domain ceramics of NdBa<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub> with high <em>T</em><sub>c</sub> and high critical currents have been prepared in air by directional solidification techniques (Bridgman growth and top seeding growth). The temperature and field dependence of the critical currents have been investigated with the magnetic field oriented along the <em>c</em>-axis and within the <em>ab</em><span>-planes to analyze the microstructural features influencing the superconducting properties. The effect of Nd</span><sub>4</sub>Ba<sub>2</sub>Cu<sub>2</sub>O<sub>10</sub> and Nd<sub>2</sub>BaO<sub>4</sub> additives on the transition temperature and the critical currents has been studied in order to examine if the concentration of antisite defects may be modified with this procedure. It has been found that no noticeable difference is generated when the samples are grown in a directional solidification procedure. We discuss as well the relevance of post-processing heat treatments in Ar and O<sub>2</sub> atmospheres on the critical currents. Finally, some clues on the general features of the magnetic phase diagram of these materials are given.</p></div>","PeriodicalId":100110,"journal":{"name":"Applied Superconductivity","volume":"6 2","pages":"Pages 119-127"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0964-1807(98)00092-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88265958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}