Spin dynamics in the low-dimensional magnet TiOCl

TL;DR

This study uses ESR to explore the spin and orbital properties of TiOCl, revealing stable orbital configurations, energy levels, and relaxation mechanisms in this low-dimensional quantum magnet.

Contribution

It provides detailed ESR analysis of TiOCl, identifying stable orbital states and elucidating spin relaxation processes, which advances understanding of its magnetic behavior.

Findings

Orbital ground state is stable below room temperature.

First excited state energy estimated at 0.3 eV.

Linewidth increases exponentially at higher temperatures.

Abstract

We present detailed ESR investigations on single crystals of the low-dimensional quantum magnet TiOCl. The anisotropy of the g-factor indicates a stable orbital configuration below room temperature, and allows to estimate the energy of the first excited state as 0.3(1) eV ruling out a possible degeneracy of the orbital ground state. Moreover, we discuss the possible spin relaxation mechanisms in TiOCl and analyze the angular and temperature dependence of the linewidth up to 250 K in terms of anisotropic exchange interactions. Towards higher temperatures an exponential increase of the linewidth is observed, indicating an additional relaxation mechanism.