Perpendicular Magnetic Recording Media (FePt-Fe$_3$Pt)/MgO With Tilted Easy Axis

Magnetic properties of tilted media with a film stack structure of MgO 2 nm/Fe₃Pt 0-5 nm [FePt 3 nm/MgO 2 nm/FePt 3 nm/MgO 4 nm]/SiO_{2/4 nm}Glass were investigated. The perpendicular coercivity and nucleation field of composite media without Fe₃Pt decrease by about 50% and 86%, respectively, from its initial value with increase in Fe₃Pt layer thickness up to 5 nm. The estimated value of alpha(=4pi(dM/dH)_H=Hc) ranges from 2-3 with increase in Fe₃Pt layer thickness up to 5 nm without significant change in the loop slope. A slight decrease in K_u is observed with increasing Fe₃Pt layer thickness. The magnitude of K_u is of the order of 10⁷ erg/cc even for Fe₃Pt layer thickness of 5 nm, suggesting media with Fe₃Pt is expected to have a high thermal stability