Mossbauer studies of BaFe11.9Mn0.1O19 by a sol-gel method

BaFe11.9Mn0.1O19 powders were prepared by a sol-gel method. Magnetic and st ructural properties of the powders were characterized by Mossbauer spectros copy, x-ray diffractometry, and vibrating sample magnetometry. X-ray diffra ction and Mossbauer measurements showed that the BaFe11.9Mn0.1O19 had an M- type hexagonal structure with a(0)=5.900 Angstrom and c(0)=23.219 Angstrom. Mossbauer spectroscopy was performed at various temperatures ranging from 13 to 800 K, and each spectrum for a temperature below the Curie temperatur e (T-C=775 +/- 5 K) was fitted with five subspectra of Fe sites in the stru cture (4f(VI), 2a, 4f(IV), 12k, and 2b). The area fractions of the subspect ra 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 tha t the valence state of the Fe ions was ferric (Fe3+). The saturation magnet ization M-s was 58 emu/g, and coercivity H-c was 5141 Oe at room temperatur e under an applied field of 15 kOe. (C) 2000 American Institute of Physics. [S0021- 8979(00)41008-X].