Study of polar relaxation processes in Sr_(1-1.5x)La_xTiO₃ ceramics by using field-induced thermally stimulated currents

Polar relaxation processes in Lanthanum doped SrTiO₃ (STO) ceramics, with general formulae Sr_(1-1.5x)La_xTiO₃, were studied by undertaking field-induced thermally stimulated currents measurements below room temperature. The experimental results obtained for doped ceramic (x = 0.0133) were analysed by using dipolar and space-charge relaxation thermally stimulated depolarization currents (TSDC) models in order to determine the nature of the relaxation processes involved. Our results reveal the existence of different relaxation processes in the temperature range 60-300 K. Whereas at low temperature, a relaxation mechanism of a dipolar type was disclosed within the temperature interval centred around 100 K, a space-charge relaxation process could be identified in the temperature range 120-300 K. The temperature dependence of the relaxation parameters will be also discussed in detail.