Determination of the Local Symmetry and the Multiferroic-ferromagnetic Crossover in Ni3-xCoxV2O8 by using Raman Scattering Spectroscopy

TL;DR

This study uses Raman scattering spectroscopy to investigate the local symmetry and phase crossover in Ni3-xCoxV2O8, revealing phonon shifts and symmetry breaking associated with the multiferroic to ferromagnetic transition.

Contribution

It provides detailed vibrational analysis and evidence of local symmetry breaking in Ni3-xCoxV2O8 during the phase crossover, advancing understanding of multiferroic materials.

Findings

Red-shifted phonon modes linked to chemical pressure effects

Evidence of local symmetry breaking in the multiferroic phase

Systematic phonon behavior across the doping range

Abstract

Comprehensive vibrational studies on the multiferroic-to-normal-ferromagnetic crossover in isostructural Ni3-xCoxV2O8 (NCVO, x = 0 - 3.0) are performed using Raman scattering spectroscopy. The systematically red-shifted phonon modes are discussed in terms of the mode Gr\"uneisen parameters, and are interpreted as a chemical pressure effect. In addition, we present evidence that the local symmetry is broken in the multiferroic phase.