Magneto-dielectric properties of Mn-doped CoFe_2O_4: Yb-doped PbZrTiO_3 multiferroic composites

摘要

The composite multiferroic materials manufactured by combining ferroelectric phase with the ferromagnetic phase offer promising applications for functional devices. The main aim of this work is on the detailed investigation of dielectric, magnetic and magnetodielectric properties of xCoMn_(0.1)Fe_(1.9)O_4-(1-x) Pb_(0.93)-Yb_(0.07)Zr_(0.52)Ti_(0.48)O_3 (x = 0.02, 0.05 and 0.08) multiferroic composites. We also present First Order Reversal Curve analysis of the multiferroic composites. The composite multiferroics were synthesized by solid state reaction method while the individual phases, Pb_(0.93)Yb_(0.07)Zr_(0.52)Ti_(0.48)O_3 and CoMn_(0.1)Fe_(1.9)O_4, were prepared by sol gel auto-combustion technique. The XRD studies confirm the phase formation of the composites with no observation of any additional phases in the systems. By studying the dielectric and magnetic properties, it was demonstrated that the increase in the ferrite content of the composites has been found to remarkably improve the dielectric and magnetic properties of the composites. The observed anomalies in the dielectric constant with the temperature results from the ferroelectric phase transition of YbPZT, and the transition temperature enhances with increasing the ferrite content in the composites. The P-E hysteresis loops of the ferroelectric phase are well saturated; however, the composites have less-saturated loops in comparison to the YbPZT phase. Both the CMnFO and the composites displayed the well saturated magnetic hysteresis loops. Also the First Order Reversal Curve (FORC) analysis of the composite multiferroics further enlightens the information about the domain state of magnetisation and the interactions in the system. All the FORC diagrams exhibited a single contour implying that all the composites have unique magnetic phase (CMnFO). The ME coupling measured as a function of applied magnetic field demonstrates enhancement with increased ferrite content. This improved ME-effect demonstrates the strong coupling between the piezoelectric and magnetostrictive phases, which eventually will expand their scope in future generation material.