Characterization and magnetic properties of Nd Bi1−Fe0.95Co0.05O3 nanopowders synthesized by combustion-derived method at low temperature

Abstract

Nd x Bi 1− x Fe 0.95 Co 0.05 O 3 ( x =0, 0.05, 0.10, 0.15) nanopowders were prepared by a combustion-derived method. The Rietvelt fitting of the X-Ray diffraction data from the Nd x Bi 1− x Fe 0.95 Co 0.05 O 3 (NBFCO) powders showed nanopowders with rhombohedral BiFeO 3 crystalline structure (R3c) for x ≤10 and a partial structural transition to orthorhombic phase (Pnma) for x =0.15. The differential thermal analysis and thermogravimetric analysis (DTA/TGA) showed a crystallization temperature of 180 °C. Transmission electronmicroscopy (TEM) images revealed that the NBFCO nanopowders were composed of fine particles under 60 nm. From Raman spectroscopy , a band of disordered anion lattice was observed at 653 cm −1 . In spite of the antiferromagnetic nature of bulk BiFeO 3 , the NBFCO nanopowders obtained displayed a ferromagnetic hysteresis loop, with coercivity about 0.1 T and remanent magnetization of 1.02–4.33 A m 2 /kg were obtained at room temperature. This ferromagnetic behavior is due to increasing and uncompensated spins at the surface and the canted internal spin by the tilt of FeO 6 octahedral units. We have developed a novel synthetic route for the preparation of ferromagnetic BFO-derived nanopowder materials by a surfactant-assisted combustion-derived method. • The structure of materials obtained is studied. • A new synthesis method was proposed to obtain ferrimagnetic–ferromagnetic BiFeO 3 nanoparticles. • Synthesis temperature does not exceed 200 °C. • The obtained nanoparticles have sizes less than 52 nm.