Effect of annealing on dielectric behavior and conduction transport of Bi doped SrTiO3

The dielectric behavior and electrical conduction in Bi doped SrTiO3 annealed in both oxidizing (air and oxygen) and reducing atmospheres (nitrogen and hydrogen+argon) are studied in this letter. The dielectric constant and electrical conductivity are greatly enhanced in the sample annealed in a reducing atmosphere compared with that annealed in an oxidizing atmosphere. A Mott's variable range hopping (VRH) conduction mechanism, sigma=sigma(0) exp[-(T-0/T)(1/4)], is observed in a strongly reduced sample, where a significant dielectric relaxation process is present. No direct correlation is found between the VRH conduction and the dielectric relaxation. The underlying physics of these results are briefly discussed. (c) 2006 American Institute of Physics.