Influence of Cr~(3+) doping on multiferroic properties in the morphotropic phase boundary compositions of BiFeO_3-PbTiO_3 system

摘要

In this paper, we have investigated the effect of Cr3+ substitution on the crystal structure, microstructure, dielectric and magnetic behavior of the morphotropic phase boundary (MPB) composition of the multiferroic ceramic 0.675BiFe((1-x))Cr(x)O(3)-0.325PbTiO(3) (x = 0, 0.02 and 0.05). The average grain size of the specimens increased from similar to 150 nm for x = 0 to 470 nm for x = 0.05. Rietveld refinement analysis of the X-Ray powder diffraction patterns confirmed the coexistence of multiphase i.e. monoclinic Cc and tetragonal P4 mm polymorphs for all the compositions. The system exhibits weak ferromagnetism for x = 0.05. We estimated the magnetoelectric interaction constant (gamma similar to 0.31) for x = 0.05 by Ginzburg-Landau theory. The value of magnetoelectric coupling coefficient is found to be 0.054 mV/cm-Oe, 0.073 mV/cm-Oe, 0.133 mV/cm-Oe for x = 0, 00.02 and 0.05, respectively. High temperature dielectric data also reveals that Curie temperature decreases with increasing Cr3+ concentration.