Polarization-induced selective growth of single-crystal heterostructured multiferroic nanoplates with giant magnetoelectric coupling

Single-crystal heterostructured multiferroic (PbTiO3) PTO-(CoFe2O4) CFO nanoplate composites were prepared by a simple two-step hydrothermal process. The CFO nanoparticles with the size of 20–80 nm selectively grow on the positively polarized surface of the single-crystal and single-domain PTO nanoplate. The TEM results demonstrate an epitaxial growth relation between the PTO nanoplates and CFO nanoparticles. The results of the temperature-dependence magnetization of the composites under zero field cooled (ZFC) condition show a novel broad diffuse region around the PTO ferroelectric phase transition (Tc) for the first time. The total change of magnetization (Δ M) near Tc is determined to be (2.71 ± 0.5) × 10−3 emu, a change of 46.2%, implying a giant magnetoelectric coupling in these single-crystal heterostructured multiferroic PTO-CFO nanoplate composites. Such effect has been attributed to the absence of the substrate clamping and single domain in ferroelectric PTO nanoplate.