Switching field distribution of exchange coupled ferri-/ferromagnetic composite bit patterned media

TL;DR

This paper uses micromagnetic simulations to analyze the switching field distribution and bit error rate in exchange coupled ferri-/ferromagnetic bit patterned media, considering microstructure and dipolar effects.

Contribution

It introduces a comprehensive simulation approach to evaluate switching field distributions and bit error rates in bilayer ferri-/ferromagnetic media with varying structures.

Findings

Bit error rate of 10^-4 achieved with specific bilayer media.

Switching field distribution influenced by microstructure and dipolar interactions.

Optimal layer thicknesses for minimizing error rates identified.

Abstract

We investigate the switching field distribution and the resulting bit error rate of exchange coupled ferri-/ferromagnetic bilayer island arrays by micromagnetic simulations. Using islands with varying microstructure and anisotropic properties, the intrinsic switching field distribution is computed. The dipolar contribution to the switching field distribution is obtained separately by using a model of a triangular patterned island array resembling $1.4\,\mathrm{Tb/in}^2$ bit patterned media. Both contributions are computed for different thickness of the soft exchange coupled ferrimagnet and also for ferromagnetic single phase FePt islands. A bit patterned media with a bilayer structure of FeGd($5\,\mathrm{nm}$)/FePt($5\,\mathrm{nm}$) shows a bit error rate of $10^{-4}$ with a write field of $1.16\,\mathrm{T}$.