Journal of Magnetics

The Korean Magnetics Society (한국자기학회)
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Effect of Proton Irradiation on the Magnetic Properties of Antiferromagnet/ferromagnet Structures

  • Kim, Dong-Jun (Department of Materials Science and Engineering, KAIST) ;
  • Park, Jin-Seok (Mechanical System Engineering Department, KEPCO E&C) ;
  • Ryu, Ho Jin (Department of Nuclear and Quantum Engineering, KAIST) ;
  • Jeong, Jong-Ryul (Department of Materials Science and Engineering, Graduate School of Green Energy Technology, Chungnam National University) ;
  • Chung, Chang-Kyu (New Power Development Project, KEPCO E&C) ;
  • Park, Byong-Guk (Department of Materials Science and Engineering, KAIST)
  • Received : 2016.02.22
  • Accepted : 2016.05.02
  • Published : 2016.06.30
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Abstract

Antiferromagnet (AFM)/ferromagnet (FM) bilayer structures are widely used in the magnetic devices of sensor and memory applications, as AFM materials can induce unidirectional anisotropy of the FM material via exchange coupling. The strength of the exchange coupling is known to be sensitive to quality of the interface of the AFM/FM bilayers. In this study, we utilize proton irradiation to modify the interface structures and investigate its effect on the magnetic properties of AFM/FM structures, including the exchange bias and magnetic thermoelectric effect. The magnetic properties of IrMn/CoFeB structures with various IrMn thicknesses are characterized after they are exposed to a proton beam of 3 MeV and $1{\sim}5{\times}10^{14}ions/cm^2$. We observe that the magnetic moment is gradually reduced as the amount of the dose is increased. On the other hand, the exchange bias field and thermoelectric voltage are not significantly affected by proton irradiation. This indicates that proton irradiation has more of an influence on the bulk property of the FM CoFeB layer and less of an effect on the IrMn/CoFeB interface.

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