Compositional Microstructure of Perpendicular Magnetic Recording Media

The microcolumnar structure of Co-Cr film has been studied using chemical etching. Only the columns are dissolved, leaving the column boundaries with a micro-honeycomb structure. From compositional analysis of the etchant after etching, Cr segregated column boundaries have been confirmed to exist even in Co-Cr films sputtered at high sputtering rates. Co-Cr films with higher Hc show sharper and narrower grain boundaries of a higher Cr content. It is concluded that the degree of Cr segregation is a very important factor in the control of the magnetic properties of Co-Cr films.