Strain-Induced Magnetoelectric Coupling in Fe 3 O 4 /BaTiO 3 Nanopillar Composites.

Magnetoelectric coupling properties are limited to the substrate clamping effect in traditional ferroelectric/ferromagnetic heterostructures. Here, Fe 3 O 4 /BaTiO 3 nanopillar composites are successfully constructed. The well-ordered BaTiO 3 nanopillar arrays are prepared through template-assisted pulsed laser deposition. The Fe 3 O 4 layer is coated on BaTiO 3 nanopillar arrays by atomic layer deposition. The nanopillar arrays and heterostructure are confirmed by scanning electron microscopy and transmission electron microscopy. A large thermally driven magnetoelectric coupling coefficient of 395 Oe °C -1 near the phase transition of BaTiO 3 (orthorhombic to rhombohedral) is obtained, indicating a strong strain-induced magnetoelectric coupling effect. The enhanced magnetoelectric coupling effect originated from the reduced substrate clamping effect and increased the interface area in nanopillar structures. This work opens a door toward cutting-edge potential applications in spintronic devices.