Influence of Gd/Nb on activation energy, relaxation response, impedance, Nyquist plots and dielectric studies at high frequency of BaTiO3-Li0.5Fe2.5O4 solid compounds

Abstract

The Gd/Nb doped ferroelectric- ferrite solid composite having a generic formulae (0.9)BaTi (1-2x) GdxNbxO3 – (0.1)Li0.5Fe2.5O4 (x = 0, 0.05 and 0.1) synthesized using a normal solid state method. The frequency dependent of impedance spectroscopic studies at different temperatures, relaxation time with temperature, estimate the activation energy, Nyquist plots, the high frequency dielectric permitivity (ε′) and dielectric dissipation at 30 °C have been observed. The real impedance (Z′) peaks of all samples are merging in the high frequency region at all temperatures represent a feasibility of liberation of space charge polarization in the samples. As and when an increase in temperature, the maximum impedance Z′′max peak moved towards higher frequency. The relaxation time (τ) of all composites decrease steeply with increase temperature. The activation energy of BLF reduces as when Gd/Nb doped in BLF which indicates change in degree of freedom of dipoles to orient itself in the applied field direction. In Nyquist plots, all composites exhibit single semicircle at all temperatures, which represents the Debye type of relaxation exist in the composites. The dielectric permitivity (ε′) of all composites decreases steeply up to 1 GHz frequency beyond that its exhibits as complex behavior. The dielectric dissipation of all the samples exhibit jumping behavior due to Debye relaxation at high frequency region.

Keywords

• Impedance spectroscopy
• Relaxation time
• Activation Energy
• Nyquist plots
• High frequency
• Dielectric permitivity (ε′)