Effect of Nd and Ti doping on crystal structure refinement, optical, dielectric and magnetic properties of Bi 0.90 Nd 0.10 FeO 3 multiferroic

Systematic studies on Nd and Ti co-substituted BiFeO3 i.e. Bi0.90Nd0.10Fe1-xTixO3 (x=0.10, 0.15, 0.20) polycrystalline ceramic was carried out. Rietveld refinement of XRD patterns and Raman spectra confirmed the formation of mixed phase (R3c+P1) at room temperature. FESEM micrograph depicts that grain size reduces with increase in Ti concentration. Dielectric characterization of all the compositions was recorded in the frequency range 100 Hz to 7 MHz at different elevated temperatures. The value of dielectric constant as well as tangent loss increases with increase in Ti concentration from x=0.10 to x=0.20. An anomalous peak in the dielectric constant curve was detected in the vicinity of antiferromagnetic transition temperature. Magnetic studies indicate that weak ferromagnetism is induced. Cole-Cole plots revealed that a modification in the resistive and capacitive behaviour of the ceramics is detected and exhibited NTCR character. Also the value of resistivity enhances with Ti concentration which confirms reduction in leakage current. A maximum remnant magnetization Mr=5.22 memu/g and coercive field Hc=244.09 Oe was observed for composition x=0.15. The enhancement in value of remnant polarisation with Ti concentration might be due to lattice distortion and reduction in leakage current.