High-field recovery of the undistorted triangular lattice in the frustrated metamagnet CuFeO2

TL;DR

This paper investigates the high-field magnetic behavior of CuFeO2, revealing the recovery of an undistorted triangular lattice at high fields and emphasizing the roles of spin-phonon coupling and anisotropy.

Contribution

It demonstrates the high-field recovery of the undistorted triangular lattice in CuFeO2 and provides a phenomenological model explaining the magnetization behavior.

Findings

Identification of an additional high-field phase transition at 58 T.

Recovery of isotropic behavior above the transition.

Importance of spin-phonon coupling and anisotropy in magnetization.

Abstract

Pulsed field magnetization experiments extend the typical metamagnetic staircase of CuFeO2 up to 58 T to reveal an additional first order phase transition at high field for both the parallel and perpendicular field configuration. Virtually complete isotropic behavior is retrieved only above this transition, indicating the high-field recovery of the undistorted triangular lattice. A consistent phenomenological rationalization for the field dependence and metamagnetism crossover of the system is provided, demonstrating the importance of both spin-phonon coupling and a small field-dependent easy-axis anisotropy in accurately describing the magnetization process of CuFeO2.