Journal of the Korean Magnetics Society (한국자기학회지)

The Korean Magnetics Society (한국자기학회)
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Properties of Exchange Bias Coupling Field and Coercivity Using the Micron-size Holes Formation Inside GMR-SV Film

GMR-SV 박막내 미크론 크기의 홀 형성을 이용한 교환결합세기와 보자력 특성연구

  • Bolormaa, Munkhbat (Department of Oriental Biomedical Engineering, Sangji University) ;
  • Khajidmaa, Purevdorj (Department of Oriental-western Biomedical Engineering, Sangji University) ;
  • Hwang, Do-Guwn (Department of Oriental Biomedical Engineering, Sangji University) ;
  • Lee, Sang-Suk (Department of Oriental Biomedical Engineering, Sangji University) ;
  • Lee, Won-Hyung (Department of Physics, Penn State University) ;
  • Rhee, Jang-Roh (Department of Nanophysics, Sookmyung Women's University)
  • 벌러르마 (상지대학교 보건과학대학 한방의료공학과) ;
  • 카지드마 (상지대학교 대학원 동서의료공학과) ;
  • 황도근 (상지대학교 보건과학대학 한방의료공학과) ;
  • 이상석 (상지대학교 보건과학대학 한방의료공학과) ;
  • 이원형 (펜실베이아 주립대학교 물리학과) ;
  • 이장로 (숙명여자대학교 나노물리학과)
  • Received : 2015.06.05
  • Accepted : 2015.06.18
  • Published : 2015.08.31
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Abstract

The holes with a diameter of $35{\mu}m$ inside the GMR-SV (giant magnetoresistance-spin valve) film were patterned by using the photolithography process and ECR (electron cyclotron resonance) Ar-ion milling. From the magnetoresistance curves of the GMR-SV film with holes measuring by 4-electrode method, the MR (magnetoresistance ratio) and MS (magnetic sensitivity) are almost same as the values of initial states. On other side hand, the $H_{ex}$ (exchange bias coupling field) and $H_c$ (coercivity) dominantly increased from 120 Oe and 10 Oe to 190 Oe and 41 Oe as increment of the number of holes inside GMR-SV film respectively. These results were shown to be attributed to major effect of EMD (easy magnetic domian) having a region positioned between two holes perpendicular to the sensing current. On the basis of this study, the fabrication of GMR-SV applying to the hole formation improved the magnetoresistance properties having the thermal stability and durability of bio-device.

고감도 바이오센서용 거대자기저항-스핀밸브(Giant magnetoresistance-spin valve; GMR-SV) 박막소자의 미세패턴 공정으로 인한 교환결합력과 보자력 약화 문제를 해결하고자 전자사이크로트론 공명(Electron Cyclotron Resonance) Ar-이온 밀링을 이용하여 GMR-SV 박막에 지름 $35{\mu}m$인 원형 모양의 홀(Hole)을 패턴닝 하였다. GMR-SV를 4-단자법으로 측정한 자기저항 곡선으로부터 홀 개수가 많아질수록 자기저항비와 자장감응도는 홀이 없을 때 측정된 초기값과 같은 값을 유지하였고, 교환결합세기와 보자력은 120 Oe에서 190 Oe, 10 Oe에서 41 Oe로 크게 향상되었다. 이러한 현상은 GMR-SV 박막내의 자화용이축과 같은 방향을 띄고 센싱 전류의 방향과 수직인 공간에 위치하는 용이 자구영역(Easy magnetic domain; EMD)의 역할에 기인하는 결과를 보여주었다. GMR-SV 바이오 소자 제작시 폭을 넓게 하고 소자내부에 홀의 개수를 증가시켜 발생하는 EMD 효과가 자기저항특성을 향상시킬 수 있었다.

Keywords

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