(Sr,Mn)TiO3-a magnetoelectrically coupled multiglass

Extending the framework for multiferroic materials, in which long-range electric and magnetic orderings coexist, we present a novel 'multiglass' concept, where two different glassy states occur simultaneously. It applies to Sr0.98Mn0.02TiO3 ceramics, where the Mn2+ dopant ions are at the origin of both polar and spin glasses. Spin freezing is initiated at the dipolar glass temperature, Tg∼38 K. Below Tg, both glass phases are independently verified by memory and rejuvenation effects. Strong biquadratic interaction of the Mn2+ spins with the optic soft mode of the incipient ferroelectric host crystal SrTiO3 explains the high spin glass temperature and comparably strong higher order magnetoelectric coupling between the polar and magnetic degrees of freedom.