MALTS: A tool to simulate Lorentz Transmission Electron Microscopy from micromagnetic simulations

TL;DR

MALTS is a versatile software tool that simulates Lorentz TEM contrast from micromagnetic simulations, integrating with existing micromagnetic codes to facilitate analysis of magnetic nanostructures.

Contribution

It introduces a generalized, user-friendly tool that combines micromagnetic simulations with LTEM contrast modeling, enabling broader application and standardization.

Findings

Good agreement with experimental LTEM images

Flexible simulation of various magnetic nanostructures

Integration with MuMax enhances usability

Abstract

Here we describe the development of the MALTS software which is a generalised tool that simulates Lorentz Transmission Electron Microscopy (LTEM) contrast of thin magnetic nanostructures. Complex magnetic nanostructures typically have multiple stable domain structures. MALTS works in conjunction with the open access micromagnetic software Object Oriented Micromagnetic Framework or MuMax. Magnetically stable trial magnetisation states of the object of interest are input into MALTS and simulated LTEM images are output. MALTS computes the magnetic and electric phases accrued by the transmitted electrons via the Aharonov-Bohm expressions. Transfer and envelope functions are used to simulate the progression of the electron wave through the microscope lenses. The final contrast image due to these effects is determined by Fourier Optics. Similar approaches have been used previously for simulations of specific cases of LTEM contrast. The novelty here is the integration with micromagnetic codes via a simple user interface enabling the computation of the contrast from any structure. The output from MALTS is in good agreement with both experimental data and published LTEM simulations. A widely-available generalized code for the analysis of Lorentz contrast addresses is a much needed step towards the use of LTEM as a standardized laboratory technique.