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The resistivity and magnetic susceptibility ofthe quenched samples for the Y-Ba-Cu oxideswere measured at room temperature.Themeasurement for the temperature dependence of theamorphous Bi-Sr-Ca-Cu oxides with differentheat treatment temperature was made.Theresistivity and the parameters C in the formulax=X_0+C/(T-0)of the quenched samples forY-Ba-Cu oxides decreased with lowering quenchtemperature,and their susceptibility did not varymonotonously with quench temperature.The tem-perature dependence of the amorphousBi-Sr-Ca-Cu oxides gradually deviates fromCurie-Weiss law with increasing heat treatmenttemperature.The local magnetic moments forY-Ba-Cu and amorphous Bi-Sr-Ca-Cu oxidesgradually decrease with decreasing quench tempera-ture or increasing heat treatment temperature. 相似文献
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用不同的熔化方法和后续热处理制备了BSCCO系超导体,研究了冷却速度、退火温度、退火时间和不同熔化方法对相变的影响,运用X射线衍射,光学显微镜,电子探针,差热分析,热重分析,导电性和抗磁性测量等分析了组织、结构和性能,结果表明,名义成分为Bi_2(Sr,Ca)_3Cu_2O_x的熔体在空气中凝固时,Bi_2(Sr,Ca)_3Cu_2O_(8+δ)(简称2212)超导相是较稳定的相;包含Bi_2(Sr,Ca)_2CuO_(6+δ)(简称2201)相的产物是易生成的亚稳相;在急冷条件下生成非晶后两者通过后续热处理可以转变成2212相,最佳退火温度在780-870℃间,非晶相也可转变成2201相,激光浮区熔化法(LFZM)制成的2201相退火后易转变成片状或纤维状的2212相,有利于改善超导相颗粒间的连接,提高临界电流密度 相似文献
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