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We prepared bulk samples of SrLaLiTe1-xGdxO6; 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]

SrLaLiTe1-xZnxO6; x = 0,0.1,0.2,0.3 were investigated for their structural, optical and dielectric properties. The compositions were found to be monoclinic with the P21/n space group. Rietveld refinement of the X-ray data revealed a change in the cell volume and monoclinic cell angle β. The x = 0 composition exhibited the ordered double perovskite structure SrLaLiTeO6 with Li+ and Te6+.Tolerance factor and tilting angle calculations indicated a change in symmetry due to tilt of the octahedra and bending of Li–O–Te/Zn. FTIR studies confirmed that molecular bonds are present in the double perovskite structure. UV–visible reflectance measurements revealed a drop in the band gap energy indicating that the doped compositions have a better ability to conduct. SEM and EDX studies showed all compositions having an almost uniform distribution in terms of their shape, particles were grouped together, and confirmation of the element composition. Impedance spectroscopy studies indicated that the AC conductivity increases as the frequency increases. Single dielectric relaxation is also seen to be present in all compositions due to a decline in the grain resistance Rg. Cole–Cole plots revealed a non-Debye type of relaxation phenomena due to imperfections in all compositions. Dielectric studies indicated a decrease in the dielectric constant and loss with increasing frequency due to a drop in net polarization. [ABSTRACT FROM AUTHOR]

Zn(1−x)CoxO nanoparticles with (x = 0.05, 0.10, 0.15 and 0.20) were prepared by combustion method. Here we report our findings on electrical properties carried out on these materials from room temperature to 500 °C. Thermopower investigations carried out on the materials resulted in Seebeck coefficient showing a transition from positive to negative values with 'x' dependent enhancements. The material that exhibits a p-type semiconductor character at room temperature translates into an n-type of semiconductor at higher temperatures beyond 90 °C marked by a first order transition. Electrical resistivity and the activation energy being interrelated are seen to decrease with rising temperature due to increase in charge carrier concentration. Dielectric constant (ε) and dielectric loss (tan δ) investigated as a function of frequency showed nearly exponential decline in their values with increasing frequency for all the samples. However temperature dependent 'ε' and 'tan δ' show a peaking behaviour at lower temperatures with increasing trend at higher temperature as a result of increase in dielectric polarization. The DMS materials being ferromagnetic at room temperature are good temperature dependent semiconductors with high dielectric constant. [ABSTRACT FROM AUTHOR]