Models of Advance Recording Systems: A Multi-timescale Micromagnetic code for granular thin film magnetic recording systems

TL;DR

This paper introduces MARS, an open-source multi-timescale micromagnetic simulation code that integrates three solvers to accurately model magnetic recording systems across different timescales, from nanoseconds to years.

Contribution

The paper presents a novel multi-timescale micromagnetic code combining three key solvers, enabling comprehensive simulations of magnetic recording systems over a wide range of timescales.

Findings

Enables simulation of entire HAMR process in a single run.

Accurately models magnetisation dynamics near and far from Curie point.

Bridges atomistic parameters with macroscopic recording media behavior.

Abstract

Micromagnetic modelling provides the ability to simulate large magnetic systems accurately without the computational cost limitation imposed by atomistic modelling. Through micromagnetic modelling it is possible to simulate systems consisting of thousands of grains over a time range of nanoseconds to years, depending upon the solver used. Here we present the creation and release of an open-source multi-timescale micromagnetic code combining three key solvers: Landau-Lifshitz-Gilbert; Landau-Lifshitz-Bloch; Kinetic Monte Carlo. This code, called MARS (Models of Advanced Recording Systems), is capable of accurately simulating the magnetisation dynamics in large and structurally complex single- and multi-layered granular systems. The short timescale simulations are achieved for systems far from and close to the Curie point via the implemented Landau-Lifshitz-Gilbert and Landau-Lifshitz-Bloch solvers respectively. This enables read/write simulations for general perpendicular magnetic recording and also state of the art heat assisted magnetic recording (HAMR). The long timescale behaviour is simulated via the Kinetic Monte Carlo solver, enabling investigations into signal-to-noise ratio and data longevity. The combination of these solvers opens up the possibility of multi-timescale simulations within a single software package. For example the entire HAMR process from initial data writing and data read back to long term data storage is possible via a single simulation using MARS. The use of atomistic parameterisation for the material input of MARS enables highly accurate material descriptions which provide a bridge between atomistic simulation and real world experimentation. Thus MARS is capable of performing simulations for all aspects of recording media research and development. This ranges from material characterisation and optimisation to system design and implementation.