Magnetic phase diagram, critical behaviour and 2D-3D crossover in a triangular lattice antiferromagnet RbFe(MoO4)2

TL;DR

This study investigates the magnetic phase diagram, critical behavior, and dimensional crossover in the triangular lattice antiferromagnet RbFe(MoO4)2, revealing agreement with 2D XY model predictions and a transition from 2D to 3D thermodynamic behavior.

Contribution

It provides experimental evidence of 2D-3D crossover and critical phenomena in a triangular lattice antiferromagnet, aligning with theoretical models.

Findings

Magnetic phase diagram matches 2D XY model predictions

Observed crossover from T^2 to T^3 specific heat behavior

Critical indices consistent with 2D XY universality class

Abstract

We have studied the magnetic and thermodynamic properties as well as the NMR spectra of the Heisenberg antiferromagnet RbFe(MoO4)2. The observed temperature dependence of the order parameter, the critical indices and the overall magnetic H-T phase diagram are all in a good agreement with the theoretical predictions for a 2D XY model. The temperature dependence of the specific heat at low temperature demonstrates a crossover from a T^2 law characteristic of a two-dimensional antiferromagnet to a three-dimensional T^3 law.