二次元周期構造を有する Co-Pt 反強磁性結合積層体の磁気特性

抄録

  The influence of two-dimensional nano-structures on magnetic properties has been investigated in perpendicular antiferromagnetically coupled (AFC) Co₈₀Pt₂₀ stacked films. The AFC-samples consisted of [Co-Pt(10 nm)/Ru(0.46 nm)/Co-Pt(5 nm)] stacked layers, and the magnetization of the 5-nm-thick bottom Co-Pt layers was firstly reversed by AF-coupling. Hexagonal arrays of dots and holes were formed on both (top and bottom) Co-Pt layers and only on the top Co-Pt layer. The interlayer exchange coupling between the top and bottom Co-Pt layers across very thin Ru interlayer of 0.46 nm in thickness was kept even after the nanofabrication of about 100 nm in diameter. The coercivity of dot arrays markedly increased with a decrease in dot diameter, while the magnetic properties of hole arrays were less influenced by the nanoscale patterning. The magnetization rotation of AFC-samples with the patterned top layer changed from multiple to continuous reversal processes with decreasing in patterning size. For the top layer patterned sample, the minor loop shift of the 100-nm-dot arrays decreased from 240 to 140 kA/m, while the 100-nm-hole arrays showed almost the same strength of interlayer exchange coupling compared with that of continuous film prior to patterning.