High magnetic-dielectric tunability in Ni nanocrystals embedded BaTiO3 films

A large lattice mismatch (>10%) system was designed, consisting of epitaxial BaTiO3 matrix and Ni nanocrystals (NCs). The interfacial stress was fully released by the formation of three-dimensional islands Ni NCs with a preferred (111) orientation. We further demonstrated that the elastic energy of (111) was much smaller than the (100) planes. The remarkable dielectric tunability of 0.41 at 100 Oe was obtained, attributing to the large magnetoelastic energy Delta H= 0.096 eV. Due to the smaller magnetoelastic energy density (2.32 x 10(6)j/m(3)) relative to the magnetocrystalline anisotropy energy densities, magnetically polarized Ni NCs could overcome the anisotropy field and diamagnetism of the BaTiO3 matrix, resulting in the easily tunable dielectric properties with a weak magnetic field. These discoveries represent great potential for magnetoelectric devices. (C) 2019 Elsevier B.V. All rights reserved.