한국초전도학회:학술대회논문집

The Korean Superconductivity Society (한국초전도학회)
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Characterization of YBCO do SQUID fabricated on sapphire substrate for biomagnetic applications

생체자기 응용을 위한 사파이어 기판 위에 제작된 YBCO dc SQUID 의 특성

  • Lim, Hae-Ryong (Korea Research Institiute of Standards and Science, Department of physics, Yeungnam University) ;
  • Kim, In-Seon (Korea Research Institiute of Standards and Science) ;
  • Kim, Dong-Ho (Department of physics, Yeungnam University) ;
  • Park, Yong-Ki (Korea Research Institiute of Standards and Science) ;
  • Park, Jong-Chul (Korea Research Institiute of Standards and Science)
  • 임해용 (한국표준과학연구원, 초전도그룹, 영남대학교 물리학과) ;
  • 김인선 (한국표준과학연구원, 초전도그룹) ;
  • 김동호 (영남대학교 물리학과) ;
  • 박용기 (한국표준과학연구원, 초전도그룹) ;
  • 박종철 (한국표준과학연구원, 초전도그룹)
  • Published : 2000.08.16
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Abstract

YBCO step-edge dc SQUID magnetometers on sapphire substrates have been fabricated. CeO2 buffer layer and YBCO films were deposited in situ on the low angle (${\sim}$35$^{\circ}$) steps formed on the sapphire substrates. Typical 5-${\mu}$m-wide junction has R$_n$ of 5 ${\omega}$ and I$_c$ of 50 ${\mu}$A with large I$_c$R$_n$ product of 250 ${\mu}$V at 77K. According to applied bias current, depth of voltage modulation was changed and maximum voltage was measured 16 ${\mu}$V. Field noise of do SQUID was measured 100${\sim}$300 fT/${\surd}^{Hz}$ in the 1 $^{kHz}$, and about 1.5 pT/${\surd}^{Hz}$ in the 1/f region. For ac bias reversal method, field noise was decreased in the 1/f region. The QRS peak of magnetocardiogram was measured 50 pT in the magnetically shielded room.

Keywords