Effect of W co-doping on the optical, magnetic and electrical properties of Fe-doped BaSnO3

The effect of W co-doping on the optical, magnetic and electrical properties of Fe-doped BaSnO3 has been studied. Polycrystalline BaSnO3, BaSn0.96Fe0.04O3 and BaSn0.95Fe0.04W0.01O3 samples were prepared using solid state reaction. In the analysis of powder X-ray diffraction patterns, the samples were found to be free of secondary phases. Diffuse reflectance spectra evidenced the substitution of Fe and W for Sn in the host BaSnO3. Micro-Raman spectra confirmed the existence of oxygen vacancies in the samples. Upon W-1% co-doping, the ferromagnetic character of Fe-4% doped BaSnO3 is suppressed drastically and its Curie temperature is reduced to 310 K from 462 K. The existence of F-centers and ferromagnetic interactions at room temperature is evidenced by the electron paramagnetic resonance and ferromagnetic resonance signals observed in the electron spin resonance spectra of the undoped and Fe-4% doped, (Fe-4% and W-1%) co-doped BaSnO3 samples respectively. Suppression of ferromagnetism upon W co-doping is due to the fact that each W6+ ion donates two electrons to the host lattice and it reduces the number of oxygen vacancies that are essential for ferromagnetism to exist in the Fe-doped BaSnO3 samples.