Search for a nematic phase in quasi-2D antiferromagnet CuCrO2 by NMR in electric field

TL;DR

This study uses combined NMR and electric polarization measurements to investigate the magnetic phases of CuCrO2, confirming the existence of a 3D-polar phase with electric polarization and refining the phase diagram.

Contribution

It introduces a novel experimental approach and provides new insights into the magnetic and electric properties of CuCrO2, confirming the 3D-polar phase hypothesis.

Findings

Confirmation of a 3D-polar phase with electric polarization

Refined phase diagram with a modified transition boundary

Identification of helmet-shaped NMR spectra linked to interplanar disorder

Abstract

The magnetic phase diagram of CuCrO2 was studied with a novel method of simultaneous Cu NMR and electric polarization techniques with the primary goal of demonstrating that regardless of cooling history of the sample the magnetic phase with specific helmet-shaped NMR spectra associated with interplanar disorder possesses electric polarization. Our result unequivocally confirms the assumption of Sakhratov et al. Phys. Rev. B \bf{94}, 094410 (2016) that the high-field low-temperature phase is in fact a 3D-polar phase characterised by a 3D magnetic order with tensor order parameter. In comparison with the results obtained in pulsed fields, a modified phase diagram is introduced defining the upper boundary of the first-order transition from the 3D-spiral to the 3D-polar phase.