Micromagnetic studies for bit patterned media above 2 Tbit/in. 2

Abstract

Bit patterned media (BPM) recording is a candidate for extremely high density magnetic recording. A micromagnetic model is built up to analyze the phase diagram of the correct-write-in condition in BPM above 2 Tb/in. 2 fabricated by lithography or ion irradiation methods. The target of the study is to acquire the relationship between the recording performance and the magnetic properties of the media. The medium includes the polycrystalline grains and grain boundary. In BPM fabricated by lithography with FCT structure, two phase diagrams of the correct-write-in condition are found for the anisotropy angular distribution Δ θ, the ratio of tetragonal anisotropy K 22 to uniaxial anisotropy K 1 and the uniaxial anisotropy distribution Δ K 1. In BPM fabricated by ion irradiation methods, two phase diagrams of the correct-write-in condition are analyzed for the ratio of saturation magnetization M′ s/ M s, anisotropy field H′ k/ H k and the exchange field H′ ex/ H ex in the ion irradiated region and the bit islands.