退火对HgBa_2Ca_2Cu_3O_（8＋δ）超导体的转变温度T_c的影响  

ANNEALING EFFECTS ON THE TRANSITION TEMPERATURE Tc OFHgBa_2Ca_2Cu_3O_(8+δ) SUPERCONDUCTOR

作　　者：邵惠民[1] 沈临江[1] 车广灿 王世栋[1] 沈剑沧[1] 吴诤[1] 华晓燕[1] 姚希贤[1] 

机构地区：[1]南京大学物理系固体微结构国家实验室,南京化工学院超导实验室,中国科学院物理所,东南大学分析中心

出　　处：《低温物理学报》1995年第2期115-118,共4页Low Temperature Physical Letters

基　　金：国家超导研究和开发中心资助

摘　　要：本文报导我们成功地合成了高Ｔｃ超导铜氧化物ＨｇＢａ２Ｃａ２Ｃｕ３Ｏ（８＋δ），并用ＸＲＤ、ＴＥＭ、交流磁化率及电阻测量对这些样品作了研究．特别是，为了更进一步提高Ｔｃ，我们对这些样品在各种气氛条件下进行了事后退火处理研究．发现：样品的超导转变温度Ｔｃ，在流动氧气中或高压氧气中退火后，获得增高；而在流动氩气中退火后其值变小．因此，由退火实验结果可知：未经退火处理的Ｈｇ－１２２３相样品处于微弱的“ｕｎｄｅｒ－ｄｏｐｅｄ”态；且似乎可以说Ｔｃ与铜的价态存在一个类似抛物线的关系．Abstract The samples of high Tc superconducting cuprate HgBa2Ca2Cu3O8+δ have been successifully synthesized and studied by X-ray diffractiion, .transmissin electron microscopy, A. C.susceptibility and resistivity. For such samples, Post-annealing treatments were carried out in various atmospheres in order to enhance Tc. The Superconducting transition temperature, Tc,o f the sample increased after annealing in either flowing oxygen or a high-pressure oxgen gas,while it decreased after annealing in flowing argon. These results indicated that the as-sintered Hg-1223 phase sample was in slightly 'under-doped' state and seem to suggest that there is a paraboliclike dependence of Tc versus the copper valence.

关 键 词：HBCCO 超导体 转变温度 退火 

分 类 号：TM262[一般工业技术—材料科学与工程]