Temperature-dependent magnetism in Fe foams via spin-lattice dynamics

TL;DR

This study uses spin-lattice dynamics to analyze how the magnetic properties of Fe foams vary with temperature and surface atom fraction, revealing linear decreases in Curie temperature and changes in critical behavior.

Contribution

It introduces a detailed analysis of temperature-dependent magnetism in Fe foams, highlighting the influence of surface atom fraction and topology on magnetic critical parameters.

Findings

Curie temperature decreases linearly with surface atom fraction

Critical exponent increases with surface atom fraction

Magnetic properties depend on surface atom coordination

Abstract

Spin-lattice dynamics is used to study the magnetic properties of Fe foams. The temperature dependence of the magnetization in foams is determined as a function of the fraction of surface atoms in foams, nsurf. The Curie temperature of foams decreases approximately linearly with nsurf, while the critical exponent of the magnetization increases considerably more strongly. If the data are plotted as a function of the fraction of surface atoms, reasonable agreement with recent data on vacancy-filled Fe crystals and novel data on void-filled crystals is observed for the critical . Critical temperature and critical exponent also depend on the coordination of surface atoms. Although the decrease we find is relatively small, it hints to the possibility of improved usage of topology to taylor magnetic properties.