Magnetic and dielectric properties of BaFe1/2Sn1/2O3-delta ceramics

Ceramic samples of barium ferrostannate BaFe1/2Sn1/2O3-delta have been prepared by the sol-gel and hydrothermal synthesis methods. To reduce the number of oxygen vacancies, annealing in oxygen has been performed. The heat capacity, magnetization, Mossbauer and dielectric spectroscopy data point to the appearance of antifer-romagnetic ordering below similar to 55 K followed by further spin glass magnetic ordering below 15 K. The giant dielectric response seems to be due to the relaxation of electrons trapped by oxygen vacancies. Comparison of the Fe K-edge X-ray absorption spectra of BaFe1/2Sn1/2O3-delta confirmed substantial difference from those of the similar stoichiometric BaFe1/2Nb1/2O3 perovskite.