Coexistence of Weak Ferromagnetism and Ferroelectricity in the High PressureLiNbO3-Type Phase ofFeTiO3

Abstract

We report the magnetic and electrical characteristics of polycrystalline ${\mathrm{FeTiO}}_3$ synthesized at high pressure that is isostructural with acentric ${\mathrm{LiNbO}}_3$ (LBO). Piezoresponse force microscopy, optical second harmonic generation, and magnetometry demonstrate ferroelectricity at and below room temperature and weak ferromagnetism below $\sim 120\mathrm{K}$. These results validate symmetry-based criteria and first-principles calculations of the coexistence of ferroelectricity and weak ferromagnetism in a series of transition metal titanates crystallizing in the LBO structure.