Temperature phase transitions in silver niobate and lithium tantalate-modified silver niobate ceramics

Krylov, A.S., Krylova, S.N., Vtyurin, A.N., (...), Tian, Y., Wei, X.// Physical Chemistry Chemical Physics.//


The temperature behaviour of 0.955 AgNbO3–0.045 LiTaO3 and AgNbO3 ceramics was studied in the range from 10 to 415 K using Raman spectroscopy. Ab initio calculations of the Raman spectra in the Pmc21 phase of AgNbO3 were carried out using three potentials (A-PZ, PBE, and PBEsol) for spectral interpretation. The peculiarities in the Raman spectra in AgNbO3 ceramics are observed and explained. The differences in the spectra of the 0.955 AgNbO3–0.045 LiTaO3 and AgNbO3 ceramics are shown. The temperatures of the structural changes in the 0.955 AgNbO3–0.45 LiTaO3 and AgNbO3 ceramics were discussed. A structural phase transition below 120 K was observed in silver niobate. A phase transition was observed at 310 K and below 150 K in 0.955 AgNbO3–0.045 LiTaO3.