Detection of para-antiferromagnetic transition in Bi2Fe4O9 powders by means of microwave absorption measurements

作者：Alvarez G^*; Contreras J; Conde Gallardo A; Montiel H; Zamorano R

来源：Journal of Magnetism and Magnetic Materials, 2013, 348: 17-21.

DOI：10.1016/j.jmmm.2013.08.014

• Electron paramagnetic resonance
• Non-resonant microwave absorption
• Magnetic transition

An electron paramagnetic resonance (EPR) study of Bi2Fe4O9 powders is carried out in X-band (8.8-9.8 GHz) and the 200-350 K temperature range. For all the temperatures, the EPR spectra show a single broad line attributable to Fe3+ (S=5/2) ions. The onset of the para-antiferromagnetic transition has been determined from the temperature dependence of the parameters deduced from EPR spectra: the peak-to-peak linewidth (Delta H-pp) and the resonant field (H-res); a weak ferromagnetism is also observed at low temperature and it is attributed to canting of Fe3+ ion sublattices in the antiferromagnetic matrix. The magnetically modulated microwave absorption spectroscopy (MAMMAS) and the low-field microwave absorption (LFMA) are used to give further information on this material. These techniques give evidence of the magnetic transition, suggesting a weak ferromagnetism at low temperature.

• 出版日期2013-12