Coupled structural and magnetic properties of ferric fluoride nanostructures: part II, a Monte-Carlo Heisenberg study

TL;DR

This study uses Monte Carlo simulations to analyze the magnetic and structural properties of nanostructured iron fluoride, revealing the effects of grain boundary topology on magnetic frustration and hysteresis behavior.

Contribution

It introduces a Monte Carlo Heisenberg model with experimental parameter tuning to explore magnetic structures in nanostructured ferric fluoride.

Findings

Antiferromagnetic grains observed

Disordered magnetic boundary regions identified

Magnetization rotation is spatially non-uniform

Abstract

We present a numerical study of the magnetic structure of nanostructured iron fluoride, using the Monte-Carlo-Metropolis simulated annealing technique and a classical Heisenberg Hamiltonian with a superexchange angle dependence. The parameters are adjusted on experimental results, and the atomic structure and topology taken from a previous atomistic model of grain boundaries in the same system. We find perfect antiferromagnetic crystalline grains and a disordered magnetic configuration (speromagnetic like) at the grain boundary, in agreement with experimental findings. Both the lowest magnetic energy and the rate of magnetic frustration are found to be dependent on the relative disorientation of crystalline grains, i.e. on the cationic topology. By simulating hysteresis loops, we find that the magnetization rotation is not spatially uniform. We conclude on possible extensions of the model.