Low-temperature dielectric properties of doped SrTiO_3 single crystals and valency of ions

摘要

This work is dedicated to the research of the dielectric parameters epsilon_0 and tan delta and the electronic state of regular and doped ions in pure and doped strontium titanate single crystals under T= 10-300 K. An anomaly of the temperature dependence of the dielectric parameters between 10 and 100 K was discovered for separate doped samples. The essential change of spectroscopic parameters and transition of some part of Ti~(4+) ions into Ti~(2+, 3+) states has been studied in detail.