Spin wave excitations in the pyrovanadate alpha-Cu2V2O7

TL;DR

This study investigates spin wave excitations in the multiferroic alpha-Cu2V2O7 using inelastic neutron scattering, revealing dispersive spin waves and the dominance of third nearest neighbor exchange interactions.

Contribution

First inelastic neutron scattering analysis of alpha-Cu2V2O7 revealing spin wave dispersions and magnetic interactions.

Findings

Dispersive spin wave excitations observed below 35 K.

Zone-boundary energy of 11 meV at 5 K.

Third nearest neighbor exchange interaction dominates magnetism.

Abstract

The pyrovanadate alpha-Cu2V2O7 belongs to the orthorhombic (Fdd2) class of crystals with noncentrosymmetric crystal structure. Recently, the compound has been identified to be a magnetic multiferroic with a substantial electric polarization below the magnetic transition temperature TC = 35 K. Here we report the results of our inelastic neutron scattering (INS) studies on a polycrystalline sample of alpha-Cu2V2O7. Our INS data clearly show the existence of dispersive spin wave excitations below TC with a zone-boundary energy of 11 meV at 5 K.We have analyzed the data using linear spin wave theory, which shows good agreement between the experiment and calculation. The analysis is consistent with the third nearest neighbor exchange interaction playing a dominant role in the magnetism of the material.