Gd-doped SrLaLiTeO6: unraveling structural, optical and dielectric changes.

We prepared bulk samples of SrLaLiTe_1-xGd_xO₆; 0 ≤ x ≤ 0.3, using the solid-state method. Measurements carried out on the XRD data recorded at room temperature highlighted changes corresponding to the volume of the unit cell and angle β. Specifically, the undoped composition described a structure of the ordered type containing Li⁺ and Te⁶⁺. Calculations of the octahedral tilt angle indicated a transition from cubic to monoclinic symmetry, accompanied by bending and tilting of the B-O-B'(B = La, B' = Te/Gd) octahedra. FTIR measurements confirmed the existence of molecular bonds in all compositions. UV–visible spectroscopy results indicated a reduced bandgap energy, suggesting enhanced conductivity in the doped samples. SEM and EDX confirmed the elemental composition and revealed particle clustering. Impedance spectroscopy analysis demonstrated increased AC conductivity at higher frequencies. Additionally, a decrease in the grain resistance indicated single dielectric relaxation behavior. A relaxation phenomenon of the non-Debye type was revealed from the Cole–Cole plots attributed to the presence of imperfections within the samples. Dielectric properties showed a reduction in dielectric loss and constant, which was dependent on frequency, attributed to the decrease in overall polarization. [ABSTRACT FROM AUTHOR]