Synthesis and magnetic properties of Mg0.2Cr1.8−xFexO3 nanoparticles

• Published in: Journal of magnetism and magnetic materials 2013-03, Vol.330, p.159-162
• Main Authors: Mbela, Kalengay, Moyo, T., Msomi, J.Z., Öztürk, M., Akdog‘an, N.
• Format: Article
• Language: English
• Subjects: Bias; Clusters; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Corundum; Diamagnetism, paramagnetism and superparamagnetism; Exact sciences and technology; Exchange bias; Ferromagnetism; Magnetic properties; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Magnetization; Mössbauer effect; other γ-ray spectroscopy; Nanoparticle; Nanoparticles; Phase shift; Physics
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2012.10.045

We report the magnetic properties of Mg0.2Cr1.8−xFexO3 (for x=0.3, 0.5, 0.7, and 0.9) nanoparticle compounds. The oxides were produced by hydrothermal process and sintered at 600°C for 12h. The X-ray diffraction data indicate single phase corundum structure in all the samples. The Mössbauer spectra recorded at about 300K show transition from paramagnetic to ordered magnetic spin state at x=0.5. The magnetization data reveal cluster-glass-like behavior of weakly ferromagnetic clusters in a dominant antiferromagnetic core. The shift in hysteresis loops observed along the magnetic field axis is associated with exchange bias effect. The exchange bias field measured at 10K is also observed to correlate strongly with particle sizes. ► Prepared Mg0.2Cr1.8−xFe2O3 compounds by hydrothermal process. ► Anomalous variation of magnetization in low fields has been observed. ► The oxides exhibit exchange bias effects which appear to be sensitive to grain sizes. ► Samples with larger grains show more enhanced exchange bias effect. ► Results from 400K to 10K show evidence of strong antiferromagnetic interactions in the compounds.