Bi_2Sr_2CaCu_2O_8单晶中的反常尖锋效应  

ANOMALOUS MAGNETIZATION PEAK EFFECT IN Bi_2Sr_2CaCu_2O_8 SINGLE CRYSTALS

作　　者：王文虎[1] 李世亮[2] 陈兆甲[2] 闻海虎[2] 熊玉峰[1] 

机构地区：[1]中国科学院理化技术研究所低温事业部,北京100080 [2]中国科学院物理研究所凝聚态物理中心,北京100080

出　　处：《物理学报》2001年第12期2466-2470,共5页Acta Physica Sinica

摘　　要：使用牛津震动样品磁强计 (VSM)研究了Bi2 Sr2 CaCu2 O8单晶的磁滞回线 .在 2 0到 40K温度之间发现了反常的尖锋效应 ,随样品O含量的增加 ,发生尖锋效应的外场也相应提高 .可以认为在尖峰效应处发生了由涡漩物质的有序固态到无序固态的相变 ,在有少量点缺陷存在的BSCCO单晶相图上 ,Bsp线终止于 2 0K温度处 ,在 2 0K以下温区没有发生准格子到涡漩玻璃的相变 ,涡漩固相始终以准格子形式存在 ;可以认为尖峰效应是外场、温度。Magnetic hysteresis loops were measured on Bi2Sr2CaCu2O8 single crystals with a vibrating sample magnetometer. An anomalous second magnetization peak was observed between 20 and 40K. The magnetic fields showing peak effect in over - doped crystal were observed to be higher than the optimally doped samples. The disorder - driven transition shifted to lower fields with increasing point disorder. At lower temperatures the quasilattice transformed into a disordered solid as the field was increased above the second magnetization peak. There was not any transition from the ordered solid quasilattice to a disordered solid below 20K in schematic vortex matter phase diagram in BSCCO. The peak effect was a complicated function of magnetic field, temperature and material disorder.

关 键 词：Bi2Sr2CaCu2O8 单晶 磁滞回线 尖锋效应 相变 高温超导体 铋锶钙铜复合氧化物 

分 类 号：O511[理学—低温物理]