Interparticle spacing dependence of magnetic anisotropy and dipolar interaction of Ni nanocrystals embedded in epitaxial BaTiO3 matrix

Abstract

A quasi-periodic superlattice was designed, consisting of the epitaxial BaTiO3 single crystal matrix and the Ni nanocrystals (NCs). For the in-plane Ni NCs the statistical interparticle spacing (R) with a log-normal distribution was controlled ranging from 9 to 28 nm. With the decrease of R, the preferential orientation of the Ni NCs was changed from (001) to (111), inducing the transition of magnetic anisotropy from the out-of-plane to the in-plane direction. Increasing the in-plane R modulated the collective magnetic behavior by effectively lowering the interparticle dipolar coupling. For the Ni NCs/BaTiO3 system, it displayed a noninteracting system in the out-of-plane, and possesses an in-plane tunability between the interacting (R < 21 nm) and noninteracting (R ≥ 21 nm) system according to change the R. The increase of in-plane anisotropy energy induced the enhancement of dipole-dipole interaction among the Ni NCs.