いろいろな記録ヘッドの構造と材料に対して高周波アシスト磁気記録(microwave-assisted magnetic recording: MAMR)方式高周波発振素子(spin-torque oscillator: STO) のマイクロマグネティック解析を行っている.記録ヘッドの材料により最適な注入電流密度(Jopt)を削減することは極めて困難である一方,記録ヘッドの構造によりJoptは大きく異なり,媒体に対して斜めのギャップ中にSTO 素子を配したモデルの,媒体に対して直立したギャップにSTO素子を配したモデルに対する優位性を述べた.また,素子の形状(円柱,四角柱)に関し,円柱はJoptが低く, field generation layer (FGL)の一部を削ったモデルは回転が不安定であった.
(英)
Micromagnetic analysis was carried out for the spin-torque oscillator (STO) used for microwave-assisted magnetic recording (MAMR). It was difficult to reduce the optimum injected current density (Jopt) by optimizing the material characteristics and the write head structure significantly affected Jopt. A tilted main pole – trailing shield gap with a tilted STO gave a smaller Jopt than a write head with the STO perpendicular to the medium. We also investigated various STO structures (cylinder and cuboid with and without a cut) and found that the cylinder had smaller Jopt and the models with cuts had unstable oscillations.