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Soft X-ray Synchrotron-Radiation Spectroscopy Study of Half-metallic Mn3Ga Heusler Alloy

반쪽 금속 호이슬러 화합물 Mn3Ga의 연 X선 방사광 분광 연구

  • Seong, Seungho (Department of Physics, The Catholic University of Korea) ;
  • Lee, Eunsook (Department of Physics, The Catholic University of Korea) ;
  • Kim, Hyun Woo (Department of Physics, The Catholic University of Korea) ;
  • Kim, D.H. (Department of Physics, The Catholic University of Korea) ;
  • Kang, J.S. (Department of Physics, The Catholic University of Korea) ;
  • Venkatesan, M. (School of Physics and CRANN, Trinity College) ;
  • Coey, J.M.D. (School of Physics and CRANN, Trinity College)
  • 성승호 (가톨릭대학교 물리학과) ;
  • 이은숙 (가톨릭대학교 물리학과) ;
  • 김현우 (가톨릭대학교 물리학과) ;
  • 김대현 (가톨릭대학교 물리학과) ;
  • 강정수 (가톨릭대학교 물리학과) ;
  • ;
  • Received : 2016.11.20
  • Accepted : 2016.12.15
  • Published : 2016.12.31

Abstract

By employing photoemission spectroscopy (PES) and soft X-ray absorption spectroscopy (XAS), the electronic structure of the candidate half-metallic antiferromagnet of $Mn_3Ga$ Heusler compound has been investigated. We have studied two ball-milled $Mn_3Ga$ powder samples, one after annealing and the other without annealing, respectively. Based on the Mn 2p XAS study, we have found that Mn ions are nearly divalent in $Mn_3Ga$ and that the Mn ions having the locally octahedral symmetry and those having the locally tetrahedral symmetry are both present in $Mn_3Ga$. We have found relatively good agreement between the measured valence-band PES spectrum of $Mn_3Ga$ and the calculated density of states, which is in agreement with the half-metallic electronic structure of $Mn_3Ga$.

이 연구에서는 방사광을 이용한 연 X-선 흡수 분광법(soft X-ray absorption spectroscopy: XAS)과 광전자 분광법(photoemission spectroscopy: PES) 을 이용하여 반쪽금속 반강자성체 후보 물질인 $Mn_3Ga$ 호이슬러 화합물의 전자구조를 연구하였다. 이 연구에 사용된 시료는 full-Heusler $Mn_3Ga$로 ball milling 후 열처리하지 않은 시료와 ball milling 후 $400^{\circ}C$에서 열처리한 두 시료를 사용하였다. XAS 분석에 의하면 $Mn_3Ga$에서 Mn 이온들의 원자가는 $Mn^{2+}$ 상태임을 알 수 있었으며, 국소적으로 팔면체 대칭성을 가진 Mn 이온들과 사면체 대칭성을 가진 Mn 이온들이 섞여 있음을 알 수 있었다. 그리고 $Mn_3Ga$의 가전자띠 PES 스펙트럼은 전자구조 계산에 의한 반쪽 금속성 상태밀도와 대체로 유사함을 발견하였다.

Keywords

References

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