7Li NMR, magnetic susceptibility, and heat capacity studies on the triangular lattice system LiCrO2

TL;DR

This study investigates the magnetic properties of LiCrO2 using NMR, susceptibility, and heat capacity measurements, revealing three-dimensional magnetic behavior, magnetic correlations above T_N, and potential Kosterlitz-Thouless transition.

Contribution

It provides new insights into the magnetic behavior of LiCrO2, highlighting its three-dimensional character and possible topological transition, differing from similar compounds like NaCrO2.

Findings

LiCrO2 exhibits pronounced three-dimensional magnetic behavior.

Magnetic entropy suggests correlations above T_N.

Possible Kosterlitz-Thouless transition at 55 K.

Abstract

We report 7Li NMR, magnetic susceptibility, and heat capacity measurements on the triangular lattice Heisenberg antiferromagnet compound LiCrO2. We find that in contrast to NaCrO2, magnetic properties of LiCrO2 have a more pronounced three dimensional character with sharp anomalies in the temperature variation of the 7Li NMR intensity and the NMR spin-lattice relaxation rate 1/T1. From heat capacity measurements we find that the total entropy related to the magnetic transition is in agreement with expectations. However, we find a significant contribution to the magnetic entropy in the range from the ordering temperature T_N to nearly 4T_N. This suggests the existence of magnetic correlations at temperatures well above T_N which might be due to the frustrated nature of the system. Based on the temperature dependence of 1/T1, we discuss the possible occurrence of a Kosterlitz-Thouless-Berezinskii transition taking place at T_KTB = 55 K in LiCrO2. Lithium depletion has no significant effect on the magnetic properties and the behaviour of Li0.5CrO2 is nearly unchanged from that of LiCrO2.