Enhancement of polarization and magnetization in polycrystalline magnetoelectric composite

Electrical control of magnetization or magnetic control of polarization offers an extra degree of freedom in materials possessing both electric and magnetic dipole moments, viz., magnetoelectric (ME) multiferroics. A microstructure with polycrystalline configurations that enhances the overall polarization/magnetization and that outperforms single crystalline configurations is identified in a 1–3 CoFe 2O 4–BaTiO 3 (or CFO–BTO) composite. The characterization of local fields corresponding to the polycrystal configuration underlines a nontrivial role played by randomness in better cross coupling mediated by anisotropic and asymmetric strains. The microscopic field (local field) profile of the composite provides rich information regarding the distribution of key parameters central to the magnetoelectric effect. The differential contractual stress level observed in the local stress profile of CFO–BTO composite upon applying an external magnetic field conforms with the previous experimental magnetostriction observed in CFO. The role played by residual stresses stemming from misalignment of the polarization in the neighboring grains in enhancing the ME coupling is briefly discussed.