軟磁薄膜陣列磁化過程外場取向相關性之研究

Field orientation dependence of magnetization reversal properties of permalloy thin film array

We investigate the ellipse arrays of permalloy elements 6.45 in long axis, 0.75 in short axis, and 35nm thick, fabricated by electron beam lithography and lift-off technique. When the interparticle spacing along short-axis is smaller than the ellipse short axis, the interparticle dipole interaction plays an important role in the magnetization reversal process. In the situation, it has been observed that hysteresis loops obtained by vibrating sample magnetometer measurements strongly depend on the field direction. The results suggest that the effect of interparticle dipole interaction and array anisotropy should be taken into account to successfully design spintronic devices.我們以電子束微影術和舉離技術製備長軸、短軸及厚度分別為6.45微米0.75微米和35奈米的軟磁橢圓陣列並加以研究。當兩薄膜粒子沿著短軸的間距小於橢圓短軸時，粒子間偶極交互作用力在磁化翻轉過程中扮演重要的角色。在此情況下，振動式磁儀所測到的磁化區線顯示出對外場方向強烈的相依性。此結果建議在設計自旋電子元件時需把粒子間偶極交互作用和陣列異向性的效應列入考慮。