Dielectric behavior of BaTiO₃–Ni composite ferroic films

Abstract

Composite ferroic BaTiO₃–Ni films with different Ni content were fabricated by radio frequency (RF) cosputtering method. Complex impedance analysis indicates that the addition of Ni has greatly reduced the resistivity of the Ni-enriched boundaries. All the composite films exhibit room temperature ferromagnetism, while the ferroelectricity of the films is degrading with increasing Ni content. Dielectric measurements reveal that below the Ni content of 22.7 at.%, the dielectric response follows the general percolation theory and the increase of dielectric constant and loss tangent with Ni addition is mainly associated with the microstructure induced nanocapacitor effect and Maxwell–Wagner interface polarization which also induces significant dielectric anomaly at low frequency range.