YBCO薄膜双晶结DCSQUID的研制  

BICRYSTAL YBCO FILM DC SQUID

作　　者：黄明强[1] 陈烈[1] 吴培均[1] 杨涛[1] 聂家财[1] 刘贵荣[1] 赵伯儒[1] 赵忠贤[1] 熊旭明[1] 周岳亮[1] 

机构地区：[1]中国科学院物理研究所国家超导重点实验室,中国科学院物理研究

出　　处：《低温物理学报》1996年第4期288-293,共6页Low Temperature Physical Letters

摘　　要：在优化ＹＢＣＯ薄膜的制备工艺和研究双晶结的电流密度Ｊｃ和结的正常态电阻尼Ｒｎ与结宽的关系的基础上，在角度差为２８度的ＹＳＺ双晶基片上设计和制作了双晶结ＤＣＳＱＵＩＤ．双晶结的Ｉ－Ｖ特性基本符合ＲＳＪ模型，结宽为４μｍ的双晶结的正常态电阻Ｒｎ为２．４Ω，在２３．４ＧＨｚ微波辐射场中观察到Ｓｈａｐｒｉｏ微波感应台阶．所研制的结宽为４μｍ的双晶结的ＤＣＳＱＵＩＤ最大电压调制深度为１５μＶ，特征电压ＩｃＲｎ为６７．２μＶ，在１Ｈｚ下磁通噪声为对应频率下磁场灵敏度为１．１ｐＴ／，能量分辨率为１．９７×１０－２８Ｊ／Ｈｚ．Abstract A way of using two different deposition tempertures was developed to supress the oxide diffusion layer between the YBCO film and the YSZ substrate.The dependances of the normal state resistance and critical current density of the bicrystal grain-boundary junctions(BGJs) on their width have been investigated.The I-V characteristics of the GBJ with width of 4μm have shown the Resistively Shunted Junction (RSJ) behavior and thermal noise rounding. Its normal state resistance Rn and characteristic voltage IcRn at 77K are 2. 4Ω and 67. 2μV respectively. The Shapiro steps have been observed in its I-V curve under 23. 4GHz RF radiation. On the basis of the results, we designed and fabricated the YBCO film BGJ DC SQUIDs by laser depositing and magnetron sputtering YBCO films on the YSZ bicrystal substrate with misorientation angle of 28°. The maximum voltage modulation depth of the SQUID with junction width of 4μm is 15μV at 77K.The flux noise of the SQUID measured at 77K in flux-locked-loop (FLL) mode is 8. 3 ×10-5, correspondent magnetic field reslution and energy reslution are 1. 1 PT/ and 1. 97 × 10-28J/Hz respectively.

关 键 词：双晶结 YBCO 薄膜 SQUID 

分 类 号：TM262[一般工业技术—材料科学与工程]