Simultaneously improved dielectric, optical and conductivity properties of SrLa1−xNdxLiTeO6 double perovskites

Abstract

In this study, SrLa _1-x Nd _x LiTeO _6 ( x = 0.00, 0.25, 0.50, 0.75, 1.00) compounds were prepared using the solid-state method, and their structural, optical, dielectric and conductivity properties were investigated. The Rietveld refinement of x-ray diffraction (XRD) data shows that the compound crystallizes in monoclinic symmetry (i.e. P2 _1 /n space group). The morphological scanning electron microscopy study reports a larger grain size when the dopant is added. The optical ultraviolet-visible light spectroscopy (UV-Vis) study reveals that the energy band gap decreases as the doping increases from x = 0.00 to 0.50. Dielectric studies using electrochemical impedance spectroscopy (EIS) characterization reveal the non-Debye trend of dielectric real permittivity ( ε′ ) with the enhancement of ε ′ at 1 MHz from x = 0.00 to 0.50. ε′ and the dielectric tangent losses (Tan δ ) show increment and decrement patterns, respectively, when the temperature is increased. The frequency-dependent conductivity ( σ _AC ) plot follows the universal power law at all temperatures, and the σ _AC behavior in SrLa _1-x Nd _x LiTeO _6 is due to the tunneling of polarons.

Keywords

• double perovskite
• structural
• optical
• dielectric
• conductivity