Magnetic and optical properties of Mn-doped BaSnO3

Polycrystalline samples of BaSn1-xMnxO3 with x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05 were prepared by solid state reaction method. Using the powder X-ray diffraction patterns, these samples were found to be free of secondary phases. The substitution of Mn for Sn is also evidenced by the gradual disappearance of the characteristic optical band gap absorption (at 3.1 eV) and disappearance of Raman modes (centered around 835 cm(-1), 1157 cm(-1) and 1473 cm(-1)) of the host BaSnO3 with increasing Mn-content. The field dependent magnetization data collected at 300 K show that the undoped BaSnO3 is diamagnetic; upon doping Mn, the diamagnetic character of BaSnO3 diminishes and the ferromagnetic character evolves gradually with increasing Mn-content. The presence of F-centers in the samples is witnessed by the electron spin resonance (ESR) spectrum and the first order Raman spectrum of BaSnO3. At room temperature, the electrical resistivity of Mn-doped BaSnO3 is of the order of 10(8) Omega m. These results suggest that the ferromagnetism in these systems is due to F-center exchange interaction. The observed ferromagnetism in these samples is also supported by ESR spectra. (C) 2009 Elsevier Ltd. All rights reserved.