Induced Magnetoelectric Response in Pnma Perovskites

We use symmetry analysis to show that the G-, C-, and A-type antiferromagnetic Pnma perovskites can exhibit magnetoelectric (ME) responses when a ferroelectric instability is induced with epitaxial strain. Using first-principles calculations we compute the values of the allowed ME response in strained CaMnO(3) as a model system. Our results show that large linear and non-linear-ME responses are present and can diverge when close to the ferroelectric phase transition. By decomposing the electronic and ionic contributions, we explore the detailed mechanism of the ME response