Dielectric relaxation in doped SrTiO 3: Transition from classical thermal activation to quantum tunnelling

Abstract

The transition from the thermally activated regime to quantum tunneling is observed in the dielectric relaxation in SrTi O3 ceramic samples doped with Mn and (MgNb). The relaxation is attributed to MnTi 4+ off-center ions and to polaronlike defects coupled to MnTi 2+ and NbTi 5+ centers. The experimental results are fitted to an Arrhenius relation and to quantum tunneling with the account of damping and phonon-assisted processes. © 2005 American Institute of Physics.