Study of Magnetic Easy Axis 3-D Arrangement in L1$_{0}$ CoPt(111)/Pt(111)/MgO(100) Tilted System for Perpendicular Recording

We report a study of angular magnetic properties of high-anisotropy L1₀ CoPt (111) films having a tilted magnetic easy axis configuration without an oblique-grain microstructure. In particular, we investigated the field dependence of remanent magnetization while rotating the magnetic field inside three intersecting planes. The out-of-plane tilting of the L1₀ c-axis (the easy axis of the tetragonal cell) was induced by using a Pt (111) underlayer deposited onto a single-crystal MgO substrate in a conventional frontal pulsed laser deposition (PLD). The observed behavior is consistent with the presence of four easy axes with mutually orthogonal in-plane projections, symmetrically tilted at 36deg with respect to the film plane. Such a system can be used, like a common single-axis tilted medium, to record information in perpendicular mode, lowering the writing field to approximately 75% of the value along the easy direction, while still maintaining the high thermal stability typical of the L1₀ alloy. Moreover, the in-plane charge compensation arising from this easy axis arrangement when a perpendicular writing field is applied may favor a media noise reduction and better performance with respect to a single-axis tilted system.