Coexistence of two ferroelectric phases and improved room-temperature multiferroic properties in the (0.70)BiFe1 − xCoxO3–(0.30)PbTiO3 system

Abstract

In the present time, the focus of many researchers is to enhance the multiferroic properties of pure and doped BiFeO3 (BFO) based materials. However, the materials community has not yet achieved the desired multiferroic properties in single doped BiFeO3. Therefore, we decided to start with the well known system BiFeO3–PbTiO3, with good ferroelectric properties, as compared to undoped BFO and Co2+ as dopant, to obtain the (0.70)BiFe1 − xCoxO3–(0.30)PbTiO3 system. In this paper, the structural, magnetic, and ferroelectric properties of (0.70)BiFe1 − xCoxO3–(0.30)PbTiO3, with 0.00 ≤ × ≤ 0.12, prepared by a simple solgel route is presented. The inclusion of Co2+ leads to notable changes in the structural and magnetic properties. X-ray diffraction studies revealed that the samples crystallize into two ferroelectric phases: rhombohedral (R3c) and tetragonal (P4mm) up to x = 0.06; afterward, it leads to nearly a single phase tetragonal structure for x = 0.09 and 0.12. The magnetic properties are enhanced in a significant manner with Co2+ doping and are ascribed to structural changes (change in Fe–O–Fe bond length) and the suppression of the spiral spin structure characteristic of BiFeO3. The theoretical analysis of the magnetic data shows that the ferromagnetic part also increases with Co2+ doping. Ferroelectric properties are also enhanced with Co doping due to a decrease in the DC current density. The observed room temperature multiferroic properties of this compound foresee great potential for magnetoelectric devices.