Mössbauer studies of BaFe11.9Mn0.1O19 by a sol–gel method

Abstract

BaFe 11.9 Mn 0.1 O 19 powders were prepared by a sol–gel method. Magnetic and structural properties of the powders were characterized by Mössbauer spectroscopy, x-ray diffractometry, and vibrating sample magnetometry. X-ray diffraction and Mössbauer measurements showed that the BaFe11.9Mn0.1O19 had an M-type hexagonal structure with a0=5.900 Å and c0=23.219 Å. Mössbauer spectroscopy was performed at various temperatures ranging from 13 to 800 K, and each spectrum for a temperature below the Curie temperature (TC=775±5 K) was fitted with five subspectra of Fe sites in the structure (4fVI, 2a, 4fIV, 12k, and 2b). The area fractions of the subspectra at 13 K were 18.0%, 10.2%, 17.5%, 46.1%, and 8.2%, respectively. The 2b site had a very large quadrupole splitting. The isomer shifts indicated that the valence state of the Fe ions was ferric (Fe3+). The saturation magnetization Ms was 58 emu/g, and coercivity Hc was 5141 Oe at room temperature under an applied field of 15 kOe.