Enhancment of ferromagnetism in Ba and Er co-doped BiFeO3 nanoparticles

Bi1-y-xBayErxFeO3 [BByExFO, (0.13 <= y <= 017, 0 <= x <= 0.2)] nanoparticles were successfully synthesized by a sol-gel method. The structural, microstructural and magnetic properties have been investigated, using X-ray diffraction, Raman scattering, field emission scanning electron microscopy (FE-SEM) and magnetometry measurements at room temperature. The refinement of X-ray diffraction pattern of BB0.15ExFO indicates a phase transition from rhombohedral (R3c) to tetragonal (P4mm) with increasing Ba content and a transition from the coexistence of rhombohedral-tetragonal phase to orthorhombic (Pbnm) in BB0.15ExFO samples with increasing Er concentration. The Raman analysis confirms crystal phase transition in BB0.15E0.1FO compounds. The FE-SEM and TEM analysis show that the average nanoparticle size is about 50-100 nm and it decreases with Er concentration. The remnant magnetisation of BB0.15E0.1FO sample (M-r=0.98 emu/g) is approximately two times greater than compared to BB0.15E0.1FO (M-r=0.51 emu/g) that may be attributed to the collapse of spin structure and modifying exchange interactions because of Er+3 doping. This enhancement in magnetic properties at room temperature can play an important role for the practical applications. (C) 2015 Elsevier B.V. All rights reserved.