Magnetoelastic effects in the 2D limit enhanced by intense magnetic fields in CrOC. – (Tristan Riccardi / LNCMI / Seminar). – 19/03/2026, 14H

Seminar LNCMI

Tristan Riccardi, LNCMI-Grenoble

Seminar LNCMI, 19/03/2026, 14H, LNCMI, Salle Pauthenet

Abstract
CrOCl is a van der Waals magnet featuring a rich phase diagram [1,2] related to its low-symmetry structure, structural phase transitions, and a subtle competition of interactions potentially leading to magnetic frustration. In a previously published work [3], we showed how, exploiting the strong magneoelastic coupling in the material, we can use Raman scattering spectroscopy, performed at variable temperature and magnetic field, to decipher the magnetic phase diagram of bulk CrOCl.

Here we extend this work to the investigation of thin flakes of CrOCl down to the single layer. While previous works on thin layers have used transport techniques and did not show a clear evolution of the properties with the thickness [4], we were able to highlight strong effects of the coupling of the lattice with the external field, leading to zone-folded phonons (produced by the magnetic supercell) or blue/red-shifts of the phonon energies at the metamagnetic transitions to build a phase diagram of the material at varying thickness. Moreover, we were able to demonstrate the existence of a strong magnetostriction effect at high magnetic field (up to 30T), present for all thicknesses down to the monolayer.

Lien Zoom : https://univ-grenoble-alpes-fr.zoom.us/j/94228207316?pwd=khTdznxeFy1ZUYkYftQ0QSox6Fz3iK.1

References:

[1] P. G. Reuvekamp. Investigation into the magnetic and the structural properties of two low-dimensional
antiferromagnets TiPO4 and CrOCl. 2014

[2] P. Gu & al. Magnetic phase transitions and magnetoelastic coupling in a two- dimensional stripy
antiferromagnet. Nano Letters. 22, 1233–1241. 2022

[3] A. Pawbake & al. Magnetic Phases and Zone-Folded Phonons in a Frustrated van der Waals Magnet.
ACS Nano. 19, 26, 23693–23702. 2025

[4] M. Zhang & al. Spin-Lattice Coupled Metamagnetism in Frustrated van der Waals Magnet CrOCl. Small.
19, 2300964. 2023