한국초전도학회:학술대회논문집

The Korean Superconductivity Society (한국초전도학회)
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Fabrication and Characterization of Step-Edge Josephson Junctions on R-plane Al$_2O_3$ Substrates

R-면 사파이어 기판 위에 제작된 계단형 모서리 조셉슨 접합의 특성

  • Lim, Hae-Ryong (Korea Research Institute of Standards and Science, Department of Physics, Yeungnam University) ;
  • Kim, In-Seon (Korea Research Institute of Standards and Science) ;
  • Kim, Dong-Ho (Department of Physics, Yeungnam University) ;
  • Park, Yong-Ki (Korea Research Institute of Standards and Science) ;
  • Park, Jong-Chul (Korea Research Institute of Standards and Science)
  • 임해용 (한국표준과학연구원, 초전도그룹,영남대학교, 물리학과) ;
  • 김인선 (한국표준과학연구원, 초전도그룹) ;
  • 김동호 (영남대학교, 물리학과) ;
  • 박용기 (한국표준과학연구원, 초전도그룹) ;
  • 박종철 (한국표준과학연구원, 초전도그룹)
  • Published : 1999.08.18
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Abstract

YBCO step-edge Josephson junction were fabricated on sapphire substrates. The steps were formed on R-plane sapphire substrates by using Ar ion milling with PR masks. The step angle was controlled in the wide range from 25$^{\circ}$ to 50$^{\circ}$ by adjusting both the Ar ion incident angle and the photoresist mask rotation angle relative to the incident Ar ion beam. CeO$_2$ buffer layer and in-situ YBa$_2Cu_3O_{7-{\delta}}$ (YBCO) thin films was deposited on the stepped R-plane sapphire substrates by pulsed laser deposition method. The YBCO film thickness was varied to obtain the ratio of film thickness to step height in the range from 0.5 to 1. The step edge junction exhibited RSJ-like behaviors with I$_cR_n$ product of 100 ${\sim}$ 300 ${\mu}$V, critical current density of 10$^3$ ${\sim}$ 10$^5$ A/ cm$^2$ at 77 K.

Keywords