Dielectric and Electrical Behavior of Apraseodymium Based Tungsten Bronze Ceramics

Abstract

AbstractThe ceramic oxide Na2Ba2Pr2W2Ti4Nb4O30 (NBPWTN) is prepared by a mechanical mixed oxide route. The compound formation and the phase are concluded from the x‐ray diffraction pattern taken at room temperature (XRD). The uniform distribution of grains of various sizes with negligible voids is studied from scanning electron micrograph of the sample pellet. The presence of dielectric dispersion and ferroelectric phase in the material is observed from the temperature‐dependent dielectric parameters at selected frequencies. The existence of ferroelectricity in the material is further confirmed by the room temperature hysteresis loop. Impedance spectroscopic studies informed about the correlation between the microstructure and electrical behavior. The frequency variation of AC conductivity refers to Jonscher's law. The temperature variation of frequency exponent term n indicates OLPT (overlapping large polaron‐tunneling) model of the conduction mechanism in the sample. NBPWTN is a strong candidate for applications involving thermistor‐related devices because of the temperature dependency of resistance. The value of temperature sensitivity coefficient β in our investigation is achieved between 2000 and 11 000 K, confirming that the material has a high‐temperature stability property and is ideal for high‐temperature electronics applications. The high room temperature dielectric constant value of the ceramic (around 500) is useful for dielectric capacitor applications.