磁界中熱処理による強磁性/反強磁性多結晶積層膜の交換磁気異方性の可逆的方向制御

概要

論文の詳細を見る
The magnetic torque of ferromagnetic/antiferromagnetic (F/AF) bilayers was analyzed to elucidate the single spin ensemble model (SSE model) as a mechanism of directional control of exchange anisotropy by thermal annealing in a magnetic field. An Ni-Fe 50 Å/Mn_<74>Ir_<26> 50 Å polycrystalline bilayer, having a blocking temperature of 220℃, was annealed at 280℃ for one hour, then cooled to room temperature under an external applied field, H_a=1 kOe. This procedure was performed four times in succession on the same bilayer, changing the H_a direction. Exchange anisotropy was induced along the respective H_a directions, while their strength did not change at all. The reversible induction of the exchange anisotropy is well explained by the change of distribution of AF spin directions of the Mn-Ir grains, according to the SSE mode. We conclude that the two-dimensional random distribution of magnetic anisotropy axes of the AF grains in the film plane, used in the SSE model, is an indispensable factor in controling the direction of exchange anisotropy of F/AF bilayers.
社団法人日本磁気学会の論文
2001-04-15