Dispersion of dielectric constants in bismuth strontium ferrite (Bi,Sr)FeO3 - x —Variable-valence perovskite-structure solid solution
Abstract
The reflection spectrum R(ν) and transmission spectrum Tr(ν) of polycrystalline solid solutions Bi0.5Sr0.5FeO2.75 are studied for the first time using submillimeter and IR spectroscopy in the frequency range 7 < ν < 4000 cm-1 at temperatures of 10 300 K. A large difference is found between the magnitudes of the dielectric susceptibility measured by contact (at a frequency of 103 Hz) and noncontact (THz range) methods. It is suggested that powerful relaxation excitations exist at frequencies below 100 cm-1 (“subphonon” region). The possible origin of the excitations is discussed.
- Publication:
-
Physics of the Solid State
- Pub Date:
- September 2007
- DOI:
- 10.1134/S1063783407090089
- Bibcode:
- 2007PhSS...49.1652T
- Keywords:
-
- 77.22.Ch;
- 77.22.Gm;
- 78.20.Ci;
- 71.28.+d