Fabrication and characterization of Nd-doped BiFeO3-KNbO3 solid solution

The polycrystalline Bi 0.35 Nd 0.15 K 0.5 Fe 0.5 Nb 0.5 O 3 (BNKF) ceramic was fabricated by the solid-state reaction method. Room temperature structural analysis using X-ray diffraction and Rietveld's analysis confirmed the crystallization of ceramic in the double-phase Tetragonal and Rhombohedral (P4mm+R3c space group) symmetry. The microstructure analysis by field-emission scanning electron microscopy (FESEM) reveals the densely packed grain distribution with different shapes and sizes. The temperature and frequency dependent dielectric parameters were studied over a broad range of temperature and frequency. The complex impedance analysis reveals a non-Debye type relaxation process and NTCR behavior of BNKF. The frequency-dependent ac conductivity curve follows the universal Jonscher power law. The optimum values of polarization at zero electric field and coercivity are 0.193 mu C/cm2 and 6.532 kV/cm respectively. The room-temperature weak ferromagnetism found in the material may be due to the breakage of the spiral spin structure in BNKF.