Role of Pb(Zr0.52Ti0.48)O3 substitution in multiferroic properties of polycrystalline BiFeO3 thin films

Abstract

Multiferroic materials are of considerable interest due to the intriguing science and application potential. Effects of Pb(Zr0.52Ti0.48)O3 (PZT) modification on the structural, electrical, ferroelectric domain structure and ferromagnetic properties of BiFeO3 (BFO) polycrystalline films were investigated in detail. A morphotropic phase boundaries between rhombohedral perovskite (R3c) and tetragonal (P4 mm) were found in the PZT modified BFO thin films. 2% and 5% PZT modified BFO films exhibit uniform surface, larger domain size, fewer domain walls density, and lower electrical conductivity comparing with the pure BFO film. The 2% and 5% PZT modified BFO thin films show well saturated P-E hysteresis loops with improved remnant polarization close to 76.8 and 96.7 μC/cm2. The improved ferroelectric and dielectric properties of the PZT modified BFO films are attributed to the modified phase structure and bond lengths of Bi-O, decreased concentration of defects and defect dipole complexes, and different domain structures. The saturated magnetizations under a magnetic field of 5 000 Oe at room temperature are 8.5, 11.4, and 14.3 emu/cm3 for the pure, 2% and 5% PZT modified BFO films, respectively. The elevated magnetic properties of PZT modified BFO may be due to the distorted spin cycloid, varied canting angle of Fe-O-Fe bond via the Zr/Ti substitution, and suppressed spiral spin structure via Pb ions substitution of Bi ions.