Origin of enhanced multiferroic properties in Bi0.85−xLa0.15HoxFeO3 nanopowders

We report an experimental study of single-phase Bi0.85−xLa0.15HoxFeO3 nanoparticles (BLHxFO-NPs) that synthesized by a sol-gel method. The Rietveld refinement of X-ray diffraction pattern of BLHxFO samples indicate a phase transition from rhombohedral (space group R3c) to orthorhombic (space group Pbnm) structure with increasing Ho content. The bond lengths and angles for all samples were determined which supports the magnetic and electrical results. The average particles size of BLHxFO-NPs has been estimated from field emission scanning electron microscopy (FESEM) images and using a standard log-normal distribution equation. The remnant magnetisation in BLHxFO-NPs increase from 0.09 emu/g for x = 0-0.35 emu/g for x = 0.25 sample at 5 K. In order to clarify origin of magnetisation behaviour in BLHxFO-NPs, a systematic investigation has been performed on the magnetisation of all samples. The frequency (f) and composition (x) dependence of relative dielectric constant (ε) and dielectric loss (tan δ) have been studied for BLHxFO nanoparticles at room temperature. The dielectric properties indicates a local maximum in sample with x = 0.25 while maximum magnetodielectric coefficient occurs in x = 0.35. Simultaneous enhancement in magnetic and dielectric properties can play an important role for the practical applications.