Monte Carlo study of half-magnetization plateau and magnetic phase diagram in pyrochlore antiferromagnetic Heisenberg model

TL;DR

This study uses classical Monte Carlo simulations to explore the magnetic phase diagram and the half-magnetization plateau in a pyrochlore antiferromagnetic Heisenberg model, revealing temperature effects and phase behavior.

Contribution

It provides the first detailed finite-temperature phase diagram of the model including biquadratic interactions and compares results with experimental data.

Findings

Half-magnetization plateau observed at low temperatures.

Strong suppression of magnetic susceptibility during the plateau.

Finite-temperature phase diagram mapped out under magnetic field.

Abstract

The antiferromagnetic Heisenberg model on a pyrochlore lattice under external magnetic field is studied by classical Monte Carlo simulation. The model includes bilinear and biquadratic interactions; the latter effectively describes the coupling to lattice distortions. The magnetization process shows a half-magnetization plateau at low temperatures, accompanied with strong suppression of the magnetic susceptibility. Temperature dependence of the plateau behavior is clarified. Finite-temperature phase diagram under the magnetic field is determined. The results are compared with recent experimental results in chromium spinel oxides.