Converse magnetoelectric effect in NiFe2O4/BaTiO3 heterostructure by electric field induced inter-ferroelectric phase transition

• NiFeO3/BaTiO3 (NFO/BT) heterostructure was fabricated.
• Orthorhombic phase in BT was stabilized after poling.
• Poling causes large compressive stress along in-plane NFO film.
• Magnetization increases along in-plane and reduces in out-of plane after poling.

Converse magnetoelectric effect was experimentally demonstrated in NiFe2O4/BaTiO3 (NFO/BT) heterostructure. Electric field induced inter-ferroelectric phase transition in BT substrate and its impact on magnetization of NFO was studied for the first time. Presence of meta-stable orthorhombic phase (Amm2) along with tetragonal (P4mm) BT was revealed from Rietveld refinement in unpoled state itself. Negative lattice mismatch between NFO film and BT substrate induces compressive stress along in-plane direction of NFO and reduces magnetoelastic anisotropy energy. Hence, large magnetization was obtained along in-plane direction compared to that of out of plane. Poling stabilizes orthorhombic phase that enhances compressive stress further along in-plane direction. Consequently, increase and decrease of magnetization was observed along in and out-of plane respectively. Observations from the present work revealed that magnetization in such heterostructures can be controlled via strain-mediated coupling by voltage which provides an opportunity in spintronic devices for low power consumption.