Phase transitions in Na_2TeO_4 ceramics

摘要

Polycrystalline samples of NaTeO_4 were prepared by conventional solid-state reaction technique at low temperature (600 deg C). X-ray powder diffraction (XRD) technique was used to check the formation of single phase NaTeO_4 compound with cell parameters a = 10.602(1) A; b = 70.622(1) A and C = 8.506(1) A in orthorhombic crystal system. Detailed studies of dielectric constant (#epsilon#) and loss tangent (tan #delta#) as a function of frequency (400 Hz-10 kHz) and temperature (- 120 deg C-260 deg C) show that the compound has two phase transitions in the ferroelectric phase.