Improvement of magnetic and R/W properties in longitudinal media by using CrX/Cr dual underlayer

The effect of in-plane lattice matching on the magnetic and read/write prop erties has been quantitatively studied in CoCr24Pt12B4 or CoCr20Pt8Ta4 medi a grown on Cr, CrMO20 and CrMo20/Cr underlayer. It is found that by using C rMo20 (5 mn)/Cr (5 nm) dual underlayer, significant improvement of magnetic and R/W properties are realized. It is clarified that: (1) the utilization of CrMo/Cr dual underlayer increases H-c mainly due to the improvement of in-plane crystallographic orientation; (2) the lattice misfit has small eff ect on the improvement of in-plane crystallographic orientation. The improv ement of in-plane crystallographic orientation by using CrX/Cr dual underla yer is suggested to be due to lattice strain at the interface of Cr and CrX underlayer, which enhances the grain growth of the magnetic layer.