# Berezinskii-Kosterlitz-Thouless Type Scenario in Molecular Spin Liquid $A$Cr$_2$O$_4$

## TL;DR

This study investigates spin relaxation in $A$Cr$_2$O$_4$ spinels, revealing unconventional behavior consistent with a generalized Berezinskii-Kosterlitz-Thouless scenario, indicating hidden internal symmetries and short-range order.

## Contribution

It demonstrates a BKT-type scenario in 3D spinels with 2D-like spin relaxation behavior, introducing a new perspective on internal symmetries in these materials.

## Key findings

- Unconventional ESR linewidth temperature dependence
- Evidence for a generalized BKT scenario in 3D spinels
- Presence of hidden internal symmetry and short-range order

## Abstract

The spin relaxation in chromium spinel oxides $A$Cr$_{2}$O$_{4}$ ($A=$ Mg, Zn, Cd) is investigated in the paramagnetic regime by electron spin resonance (ESR). The temperature dependence of the ESR linewidth indicates an unconventional spin-relaxation behavior, similar to spin-spin relaxation in the two-dimensional (2D) chromium-oxide triangular lattice antiferromagnets. The data can be described in terms of a generalized Berezinskii-Kosterlitz-Thouless (BKT) type scenario for 2D systems with additional internal symmetries. Based on the characteristic exponents obtained from the evaluation of the ESR linewidth, short-range order with a hidden internal symmetry is suggested.