Interplay of lattice, spin, and dipolar properties in CoTeMoO6 : Emergence of Griffiths-like phase, metamagnetic transition, and magnetodielectric effect

Abstract

The physical properties of the noncentrosymmetric and quasi-two-dimensional canted antiferromagnetic material ${\mathrm{CoTeMoO}}_{6}$ (CTMO) are studied. We unravel a spectrum of intriguing phenomena, including a correlated short-range-ordered Griffiths-like phase near ${T}_{G}\ensuremath{\sim}64\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, a sharp step-like metamagnetic behavior of isothermal magnetization induced by a spin-flop transition at a critical magnetic field ${H}_{\mathrm{c}}\ensuremath{\sim}1.2\phantom{\rule{0.16em}{0ex}}\mathrm{T}$, a strong dielectric anomaly, a pronounced magnetodielectric effect, and the associated weak magnetoelectric coupling at its magnetic transition temperature, ${T}_{N}\ensuremath{\sim}23.4\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The crucial roles played by spin canting in CTMO are revealed in the aforementioned strongly entangled behavior of the spin and dipolar order parameters. The observed magnetostriction effect coupled with spin-phonon coupling seems to be a key factor in influencing the observed magnetodielectric effect. In addition, our theoretical first-principles calculations predict an insulating state with a canted antiferromagnetic spin configuration that matches well with the experimental results.