The effect of the thickness ratio of magnetic layers on the microstructure and magnetic properties of (CoCrPt)97.5Nb2.5/Co75Cr13Pt12/Cr thin films

Abstract

A Co75Cr13Pt12 intermediate magnetic layer was deposited between the (CoCrPt)97.5Nb2.5 upper magnetic layer and chromium underlayer by the magnetron sputtering technique. The effect of the thickness ratio of two magnetic layers and post-annealing treatment on the microstructure and magnetic properties of the films were investigated. The magnetic characteristics of the films were obtained by magnetic force microscopy, hysteresis loops and switching field distribution curves. Although annealing had no significant effect on the layer roughness, it rotated the easy axis of the magnetic layer towards the film plane, thereby enhanced the coercivity. The results showed an impressive effect of the magnetic intermediate layer thickness and post-annealing on the improving of coercivity through isolation of the magnetic grains. Formation of a non-magnetic halo around the magnetic grains reduced the inter-granular magnetostatic interaction.