Faculty Sponsor's Department:
Materials that exhibit coupling between magnetic and electric polarization are rare and important for memory storage devices. Recently, it has been suggested that the ilmenites ATiO3 (A=Mn, Co, Ni) could have interesting magnetoelectric properties. Magnetodielectric coupling has been observed in the ilmenite MnTiO3 confirming this hypothesis. Here, we explore magnetodielectric coupling in the related compounds CoTiO3 and NiTiO3. Temperature-dependent magnetic susceptibility measurements reveal antiferromagnetic ordering below 22 K, 35 K, and 65 K for NiTiO3, CoTiO3 and MnTiO3 respectively. Heat capacity measurements reveal a change in entropy at the antiferromagnetic ordering temperature of these systems. We observe magnetodielectric coupling in CoTiO3 and NiTiO3. There is a change in the dielectric constant of these systems at the magnetic ordering temperature and a magnetic field dependence of the capacitance below the magnetic ordering temperature. This is the first report of magnetodielectric coupling in CoTiO3 and NiTiO3.