Temperature dependence of the electron spin resonance linewidth in magnetic insulators

TL;DR

This study investigates how different interactions affect the electron spin resonance linewidth in magnetic insulators across a wide temperature range, identifying dominant mechanisms at various temperatures.

Contribution

It provides a quantitative analysis of spin-spin, one-phonon, and two-phonon contributions to ESR linewidth in magnetic insulators, using Co3O4 as a case study.

Findings

Spin-spin interactions dominate below 100 K.

Two-phonon interactions are most significant above 250 K.

All three mechanisms contribute notably at intermediate temperatures.

Abstract

We analyze the temperature dependence of the electron spin resonance linewidth above the critical region in exchange-coupled magnetic insulators. The focus is on separating the contributions to the linewidth from spin-spin interactions, spin-one-phonon interactions and spin-two-phonon interactions at temperatures where the spin-spin term is constant and the one- and two-phonon terms vary as T and T^2, respectively. Taking Co3O4 as an example, we use a least squares fit over the temperature range 50 K < T < 500 K to obtain values of the three components. It is found that the spin-spin mechanism is dominant below 100 K, while the two-phonon mechanism is most important above 250 K. In the intermediate region, all three mechanisms make significant contributions.