Orientational phase transitions in anisotropic rare-earth magnets at low temperatures

TL;DR

This paper studies orientational phase transitions in anisotropic rare-earth magnets at low temperatures using the Heisenberg model, calculating temperature effects on cone angles and comparing theoretical results with experimental data on holmium.

Contribution

It introduces a detailed analysis of orientational phase transitions incorporating quantum renormalizations within the Heisenberg model, with specific application to holmium.

Findings

Quantum renormalizations significantly affect anisotropy constants.

Calculated cone angle temperature dependence matches experimental data.

The model explains the cone-plane orientational transition in holmium.

Abstract

Orientational phase transitions are investigated within the Heisenberg model with single-site anisotropy. The temperature dependence of the cone angle is calculated within the spin-wave theory. The role of the quantum renormalizations of anisotropy constants is discussed. A comparison with the experimental data on the cone-plane orientational transition in holmium is performed.