Fabrication and properties of high performance YBa_2Cu_3O_(7-δ) radio frequency SQUIDs with step-edge Josephson junctions  

作　　者：刘政豪 魏玉科 王达 张琛 马平 王越 

机构地区：[1]Applied Superconductivity Research Center,State Key Laboratory for Artificial Microstructure and Mesoscopic Physics,School of Physics,Peking University

出　　处：《Chinese Physics B》2014年第9期419-422,共4页中国物理B（英文版）

基　　金：supported by the National Basic Research Program of China(Grant No.2011CBA00106);the National Natural Science Foundation of China(Grant No.11074008);the Research Fund for the Doctoral Program of Higher Education,China(Grant No.20100001120006)

摘　　要：We describe the fabrication of high performance YBa2Cu3O7-δ （YBCO） radio frequency （RF） superconducting quantum interference devices （SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3 （LAO） substrates by employing stepedge junctions （SEJs） and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47° to 61°, which is steep enough to ensure the formation of grain boundaries （GBs） at the step edges. The YBCO film was deposited using the pulsed laser deposition （PLD） technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH. Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/φ0, a white flux noise of 29 μφ0/√Hz, and the magnetic field sensitivity as high as 80 fT/√Hz. These devices have been applied in magnetocardiography and geological surveys.We describe the fabrication of high performance YBa2Cu3O7-δ （YBCO） radio frequency （RF） superconducting quantum interference devices （SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3 （LAO） substrates by employing stepedge junctions （SEJs） and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47° to 61°, which is steep enough to ensure the formation of grain boundaries （GBs） at the step edges. The YBCO film was deposited using the pulsed laser deposition （PLD） technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH. Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/φ0, a white flux noise of 29 μφ0/√Hz, and the magnetic field sensitivity as high as 80 fT/√Hz. These devices have been applied in magnetocardiography and geological surveys.

关 键 词：superconducting quantum interference device （SQUID） YBa2Cu3O7-δ （YBCO） step-edge junction radio frequency 

分 类 号：O413[理学—理论物理]