DC and AC conductivity measurements of Bi12TiO20 photorefractive crystals doped with Ag, P, Cu and Cd

Bi12TiO20 single crystals nominally pure and doped with silver, phosphor, copper and cadmium are grown using the top seeded solution growth method (TSSG). The DC conductivity followed the Arrhenius law, with activation energies 0.4-0.82 eV for investigated crystals. The real and imaginary parts of AC conductivity are measured in the temperature range 300-550 K and frequency range 10 kHz-1 MHz. The imaginary part possesses linear frequency dependence in whole temperature range for all samples and is one to two orders of magnitude larger in comparison to the real part. According to the frequency and temperature analysis of conductivity it is established that transport mechanism in doped BTO crystals is due to charge carriers hopping between defect sites.