Finite size effects and magnetic order in the spin-1/2 honeycomb lattice compound InCu{2/3}V{1/3}O{3}

TL;DR

This study investigates the magnetic properties of the quasi-two-dimensional honeycomb lattice compound InCu{2/3}V{1/3}O{3} using various spectroscopic and magnetization techniques, revealing unexpected antiferromagnetic order despite structural disorder.

Contribution

It demonstrates that finite size effects and interlayer coupling can induce robust antiferromagnetic order in disordered honeycomb lattice materials, supported by experimental and quantum Monte Carlo results.

Findings

Development of collinear AFM sublattices below 20 K

Observation of a spin reorientation transition at 5.7 T

Finite size cluster calculations show Neel-like AFM order with staggered magnetization

Abstract

High field electron spin resonance, nuclear magnetic resonance and magnetization studies addressing the ground state of the quasi two-dimensional spin-1/2 honeycomb lattice compound InCu{2/3}V{1/3}O{3} are reported. Uncorrelated finite size structural domains occurring in the honeycomb planes are expected to inhibit long range magnetic order. Surprisingly, ESR data reveal the development of two collinear antiferromagnetic (AFM) sublattices below ~ 20 K whereas NMR results show the presence of the staggered internal field. Magnetization data evidence a spin reorientation transition at ~ 5.7 T. Quantum Monte-Carlo calculations show that switching on the coupling between the honeycomb spin planes in a finite size cluster yields a Neel-like AFM spin structure with a substantial staggered magnetization at finite temperatures. This may explain the occurrence of a robust AFM state in InCu{2/3}V{1/3}O{3} despite an unfavorable effect of structural disorder.