Origin of incoherent magnetic switching behavior in CoCrPt–SiO2 perpendicular magnetic recording media

Abstract

Magnetic switching behavior for CoCrPt–SiO2 single layer media with oxygen contents (OCs) from 4% to 10% and recording layer thickness (tmag) from 2to27nm is investigated. Significant incoherent switching, caused by domain wall motion, and large activation volume are observed at tmag⩽6nm regardless of OC, consistent with nonuniform microstructure with less grain isolation at tmag=4nm. These results support formation of a highly exchange-coupled thin magnetic layer on top of Ru interlayer, which can explain the large difference between angular dependence of Hcr predicted by the Stoner-Wohlfarth theory and the experimental values.