Structural transformation induced enhanced multiferroicity in Al3+ and Ti4+ co-doped LaFeO3

Abstract

In order to enhance the magnetoelectric property of LaFeO3, we have considered co-substitution of Al3+ and Ti4+ in La3+ and Fe3+ sites. Rietveld refinement of the observed XRD patterns confirms that the pristine (LaFeO3, LFO) crystallizes in orthorhombic Pbnm (centrosymmetric) space group whereas the doped samples (La0.9Al0.1Fe0.9Ti0.1O3, LAFTO) crystallizes in orthorhombic Pna21 (non-centrosymmetric) space group due to co-doping of Al3+- Ti4+ in LFO. Analysis of magnetic data confirms the antiferromagnetic phase of LFO and LAFTO possess ferrimagnetic spin structure with enhanced magnetization. Besides this ferroelectric polarization at room temperature is also improved in the co-doped sample of LAFTO (Pmax = 0.25 µC/cm2). Spontaneous polarization is predicted from first principle calculation for LAFTO to be ~ 12.31 µC/cm2. The dielectric loss factor of LAFTO reduces significantly and the dielectric strength is also enhanced compared to that of LFO. Experimental results are in agreement with these findings extracted from ab initio calculations using density functional theory. The present doped sample LAFTO has improved magnetic, dielectric, ferroelectric properties and magnetoelectric coupling compared to that of LFO, would have the high potential for applications in multiferroic devices.