DIELECTRIC AND FERROELECTRIC BEHAVIORS OF NOVEL PbTiO3/NiFe2O4 THIN FILMS PREPARED BY SOL–GEL METHOD

Abstract

Ferroelectric/ferromagnetic (ME) biphase composite thin films with the type of (1–x) PbTiO 3( PT )–x NiFe 2 O 4 (NFO) (x = 1–9) were successfully formed in situ by sol–gel process. The dielectric and ferroelectric behaviors of the composite thin films were investigated. The asymmetrical hysteresis loops of the composite arise from the leak current due to low resistivity of NFO. The stronger stress in the thin films due to the strong conjunction between PT and the substrate contributes to the increase (decrease) of the coercive force (the remanent polarization) with increasing the content of PT. The ME composites exhibit slight percolation effect. The high dielectric constant near the percolation threshold is attributed to the "micro-capacitors" in the composite thin films.