Dielectric and Ultrasonic Investigation of Phase Transitions in PbFe_1/2Nb_1/2O₃ Ceramics

Abstract

We have investigated dielectric and acoustic properties of PbFe_1/2Nb_1/2O₃ ceramics, obtained by conventional ceramic technology, in 120–450 K temperature interval. Dielectric response showed diffused dielectric permittivity maximum caused by ferroelectric phase transition around 380 K, but no dielectric anomalies associated with magnetic phase transition at low temperatures were observed. Formation of the polar phase was confirmed by ultrasonically detected piezoelectric sensitivity. Ultrasonic investigations using pulse-echo method showed two anomalous regions in temperature dependencies of ultrasonic velocity and attenuation, associated with magnetic and ferroelectric phase transitions.

Keywords:

• PFN
• ferroelectric
• ultrasonic velocity and attenuation

Acknowledgment

Postdoctoral fellowship of Martynas Kinka is being funded by European Union Structural Funds “Postdoctoral Fellowship Implementation in Lithuania.”