Study the influence of the precipitation of metallic Ag on the phase transitions in AgNbO3−δ perovskite

In this work, Ag/AgNbO_3-δ composite was prepared by solid-state method. Rietveld refined X-ray diffraction pattern revealed that the sample crystallized in orthorhombic (Pbcm) perovskite structure with small impurities of metallic Ag and confirmed by transmission electron microscopy technique. Fourier transform infrared analysis of this composite indicated the formation of NbO₆ octahedral structure. Raman spectroscopy of this composite revealed the suppression of the ferroelectric distortion compared with pure of AgNbO₃. X-ray photoelectron spectroscopy results revealed the existence of the Ag¹⁺, Ag⁰, Nb⁵⁺, and O^2- states as well as oxygen vacancies in this composite. UV-Vis. analysis revealed that this composite has direct and indirect band gap energies of 3.75 and 1.70 eV, respectively. Differential scanning calorimetry and dielectric measurements of Ag/AgNbO_3-δ composite revealed that the phase transitions shifted toward lower temperature compared to pure AgNbO₃ perovskite. The polarization-field hysteresis loops of this composite exhibited weak ferroelectric behavior at low electric fields. These results indicated that the lead-free Ag/AgNbO_3-δ composite is a promising material for dielectric applications, particularly in dielectric devices.