Absence of ferroelectricity in double-perovskite Y2CoMnO6 single crystals

Abstract

The rare-earth double-perovskite R2CoMnO6 family has been reported to be promising multiferroics where the predicted ferroelectric polarization along the b-axis is induced by the Co2+/Mn4+ collinear magnetic order. In this work, we report our characterizations on the structural, magnetic, dielectric, and ferroelectric behaviors of flux-grown Y2CoMnO6 single crystals. A weak ferromagnetic transition with the Curie point TC ∼ 70 K is evident in combination with a remarkable magnetic hysteresis loop along the c-axis. The earlier reported dielectric anomaly at the magnetic transition is not detected in our single crystals. In addition, the peak of each electric current curve as a function of temperature, probed along different crystallographic directions, shows serious shifting with the temperature ramping rate, excluding the intrinsic ferroelectric contribution. The measured data are not in conformity with theoretical predictions and earlier experiments on polycrystalline samples. In addition, no reliable sign for magnetoelectric coupling can be detected. The present work seems to exclude the existence of magnetism-driven ferroelectricity in Y2CoMnO6.