Microscopic model for the magnetization plateaus in NH4CuCl3

TL;DR

This paper proposes a simple microscopic model with three dimer sublattices to explain magnetization plateaus and ESR excitation modes in NH4CuCl3, predicting their disappearance under high pressure.

Contribution

It introduces a novel three-sublattice dimer model that accounts for specific magnetization plateaus and ESR observations in NH4CuCl3, advancing understanding of its magnetic behavior.

Findings

Magnetization plateaus occur at 1/4 and 3/4 saturation.

The model explains ESR excitation modes.

Plateaus predicted to vanish under high pressure.

Abstract

A simple model consisting of three distinct dimer sublattices is proposed to describe the magnetism of NH4CuCl3. It explains the occurrence of magnetization plateaus only at 1/4 and 3/4 of the saturation magnetization. The field dependence of the excitation modes observed by ESR measurements is also explained by the model. The model predicts that the magnetization plateaus should disappear under high pressure.