K+-ion substituted single crystalline BaTi2O5, Ba1−xKxTi2O5−z (x = 0 to 0.006), was prepared by floating zone method. The effect of K+-ion substitution on the electrical properties of Ba1−xKxTi2O5−z was studied using impedance spectroscopy. Ba1−xKxTi2O5−z showed ferroelectricity and ion/hole mixed conduction in the b-direction. With increasing K+ content from x = 0 to 0.006, the Curie temperature (Tc) decreased from 752 to 722 K, and permittivity decreased from 18,600 to 3970. The ionic conduction behavior (ion blocking at low frequency region) became significant by the K+ substitution showing maximum at x = 0.003. The electrical conductivity of Ba1−xKxTi2O5−z increased with increasing oxygen partial pressure, and was almost 100 times higher than that of BaTi2O5 in the temperature range of 500–650 K. The activation energy of electrical conductivity was 0.8–1.5 eV.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry