Strain Engineering Magnetic Frustration in Perovskite Oxide Thin Films

摘要

Our first-principles results show that geometric frustration can be induced in thin films of multiferroic BiFeO_3. We find that competing magnetic interactions occur in the so-called supertetragonal phase of this material, which can be grown on strongly compressive substrates. We show that the frustration level can be tuned by appropriately choosing the substrate; in fact, the phase diagram of the films presents a critical line at which the three-dimensional spin order gets annihilated. We argue that these effects are not exclusive to BiFeO_3 and predict that they also occur in BiCoO_3.