Temperature dependence of the coercive field in single-domain particle systems

TL;DR

This paper investigates how the coercive field in single-domain magnetic particles varies with temperature, introducing a generalized model that accounts for particle interactions and the coexistence of blocked and unblocked states.

Contribution

It presents a new generalized model explaining the temperature dependence of coercive fields in single-domain particles, incorporating a temperature-dependent blocking temperature and interaction effects.

Findings

The model accurately fits experimental data over 2-300K.

A temperature-dependent blocking temperature explains the coercive field behavior.

The empirical factor gamma relates particle interactions to magnetic properties.

Abstract

The magnetic properties of Cu97Co3 and Cu90Co10 granular alloys were measured over a wide temperature range (2 to 300K). The measurements show an unusual temperature dependence of the coercive field. A generalized model is proposed and explains well the experimental behavior over a wide temperature range. The coexistence of blocked and unblocked particles for a given temperature rises difficulties that are solved here by introducing a temperature dependent blocking temperature. An empirical factor gamma arise from the model and is directly related to the particle interactions. The proposed generalized model describes well the experimental results and can be applied to other single-domain particle system.