Enhanced Multiferroic Properties and Valence Effect of Ru-Doped BiFeO3 Thin Films

Multiferroic materials are of considerable interest due to the intriguing science and application potential. Effects of the Ru dopant on the structural, electrical, domain structure, and ferromagnetic properties of multi ferroic BiFeO3 (BFO) polycrystalline film have been studied. The Ru-doped BFO film (BFRO) possesses a lower electrical conductivity, uniform morphology, larger domain size, and hence fewer domain walls. The BFRO film shows a well-saturated P-E hysteresis loop with an improved remnant polarization close to 99 mu C/cm(2). The saturated magnetizations of the BFO and BFRO film are 8.69 and 16.53 emu/cm(3), respectively, under a maximum magnetic field of 5000 Oe. The improved ferroelectric, ferromagnetic, and dielectric properties of the BFRO film are ascribed to the reduced concentration of defects and defect dipole complex, valence effect of Ru ions, and a different domain behavior. The enhanced magnetic properties of BFRO arise due to the distorted spin cycloid and canting angle of Fe ions in the Ru-doped BFO film.