Structural, ferroelectric, dielectric, impedance and magnetic properties of Gd and Nb doped barium titanate-lithium ferrite solid solutions

Abstract

The Gd, Nb substituted barium titanate-lithium ferrite composite are synthesized using the normal solid state technique. The structural, morphological, ferroelectric, electric and magnetic properties of doped and undoped composites are investigated using X-ray diffraction, FESEM, P-E loop tracer, dielectric spectrometer and vibrating sample magnetometer respectively. The diffraction peaks in XRD confirm the formation of tetragonal and the ferrite peaks of composites reduce with increases in concentration of Nb and Gd in BL. The FESEM reveals the formation of dense microstructure with low pores and the average grain size of composites increase first and later it decreases when increase concentration of Gd and Nb in BL composites. The unsaturated hysteresis loops of BTG-1 and BTG-2 are representing poor ferroelectricity in the samples. The dielectric constant (ε′) of all composite exhibits high at low frequency which is decreases steeply with increasing frequency upto certain frequency beyond this it becomes constant. The impedance (Z′) of the BL, BTG-1 and BTG-2 composites shows dispersion and also impedance (Z′) of the BL, BTG-1 and BTG-2 composites are decreasing with temperature at low frequency region. The capacitance (Cp') of all composites is decreasing with decreasing temperature. The resistivity (ρ) of BL increases when Gd and Nb doped in it. The magnetic properties of BL are changing as and when Gd and Nb doped in BL composites and these properties of all composites are obtained from magnetic hysteresis loop.