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

• Published in: Results in physics 2020-09, Vol.18, p.103196, Article 103196
• Main Authors: Gajula, Ganapathi Rao, Buddiga, Lakshmi Rekha, Dasari, Madhavaprasad
• Format: Article
• Language: English
• Subjects: Activation Energy; Dielectric permitivity (ε′); High frequency; Impedance spectroscopy; Nyquist plots; Relaxation time
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2020.103196

•The impedance of BNG-1 is more than BLF and BNG-2 is due to grain size of BLF.•The maximum impedance Z′′max peak shifted towards higher frequency when the increase in temperature.•The relaxation time (τ) of all composites exhibit dispersion at low temperature and the activation energy of BLF is more than BNG-1.•when doped Gd/Nb in it which is assigned to increase resistance in the composites represents dielectric response was improved. 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.