Phase transitions in Na2TeO4 ceramics

Abstract

Polycrystalline samples of NaTeO4 were prepared by conventional solid-state reaction technique at low temperature (600 °C). X-ray powder diffraction (XRD) technique was used to check the formation of single phase NaTeO4 compound with cell parameters a = 10·602(1) angstroms; b = 70-622(1) angstroms and c = 8·506(1) angstroms in orthorhombic crystal system. Detailed studies of dielectric constant (ε) and loss tangent (tan δ) as a function of frequency (400 Hz-10 kHz) and temperature (-120 °C-260 °C) show that the compound has two phase transitions in the ferroelectric phase.