Coexistence of Weak Ferromagnetism and Ferroelectricity in the High Pressure LiNbO3-Type Phase of FeTiO3

We report the magnetic and electrical characteristics of polycrystalline FeTiO3 synthesized at high pressure that is isostructural with acentric LiNbO3 (LBO). Piezoresponse force microscopy, optical second harmonic generation, and magnetometry demonstrate ferroelectricity at and below room temperature and weak ferromagnetism below similar to 120 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.