Magnetic properties of a buckled honeycomb lattice antiferromagnet

TL;DR

This study investigates the magnetic properties of a frustrated buckled honeycomb lattice antiferromagnet Co3ZnNb2O9, revealing complex magnetic behavior, phase transitions, and potential for exotic phases and magnetocaloric applications.

Contribution

It provides the first detailed thermodynamic analysis of Co3ZnNb2O9, highlighting its long-range magnetic order, field-induced transitions, and magnetocaloric effects in a frustrated honeycomb lattice.

Findings

Sharp magnetic transition at 14 K indicating long-range order

Field-induced spin-flop transition at 1.2 T

Magnetocaloric entropy change of 2.81 J/kg·K

Abstract

The intriguing interplay between competing degrees of freedom in frustrated magnets can lead to non-trivial magnetic phenomena with exotic low-energy excitations that are highly relevant for addressing some of the fundamental questions in quantum condensed matter as well as potential technological applications. Herein, we report the synthesis and thermodynamic results on a frustrated magnet Co3ZnNb2O9. The Co2+ moments constitute buckled AB-type honeycomb layers in the ab-plane. The temperature-dependent magnetic susceptibility shows a sharp anomaly at 14 K, indicating the onset of long-range magnetic ordering. The Curie-Weiss fit of the magnetic susceptibility above 100 K, yields a Curie-Weiss temperature of -70 K, suggesting strong antiferromagnetic (AFM) interactions between the Co2+ spins and an effective magnetic moment of 5.54 muB, indicating the presence of unquenched orbital angular momentum. A field-induced spin-flop-like metamagnetic transition below the ordering temperature is characterized by a critical magnetic field of 1.2 T. The specific heat shows a lambda-type anomaly at 14 K, confirming the presence of long-range magnetic ordering, due to finite interlayer interaction. Interestingly, our study of the magnetocaloric effect near the transition temperature revealed an entropy change of 2.81 J/kg.K, which is ascribed to competing interactions, underlying anisotropy, and reduced net magnetization lead to relatively small isothermal entropy changes that suggest that frustrated honeycomb magnets are promising contenders for field-induced exotic phases and magnetocaloric response.