極薄パーマロイ薄膜の誘導磁気異方性とその温度依存性

概要

論文の詳細を見る
The induced uniaxial anisotropy field H_k in very thin Ni_<79>Fe_<21> films, sandwiched by seed and protective Ta layers, was investigated. Films prepared by using a UHV sputtering process show a very sharp fiber texture of fcc-<111> even with a film thickness of 3 nm. The H_k, value was found to decrease as the film thickness decreases below 20 nm, even after an annealing procedure in a magnetic field. The change in the induced anisotropy energy K_u was measured as a function of the temperature while applying a dc magnetic field parallel to the hard axis of magnetization. The value of K_u of as-deposited thin films decreases significantly with increasing temperature from 50℃ to 100℃. The K_u reduction in a film of 5 nm reaches 〜40% of that of the original value. It is likely that the K_u reduction at temperatures below 100℃ is mainly caused by alignment of atom pairs at film surfaces. The thickness of film surfaces with highly mobile atoms was estimated to be 5-6 A. The high mobility of surface atoms may disrupt the alignment of atom-pairs parallel to the field direction during the film deposition and annealing process, resulting in the smaller H_k of very thin films.
2002-05-01