Effect of titanium ion substitution in the barium hexaferrite studied by Mossbauer spectroscopy and X-ray diffraction

A series of M-type barium hexaferrite has been synthesized in a glass melt by partially substituting the Fe2O3 with TiO2 for investigation of their structure. The glass melt has the basic composition (mol%): 40 BaO + 33 B2O3 + (27-x) Fe2O3 + x TiO2 with x = 0, 3.6, 5.4 and 7.2 mol% TiO2. The substituted ferrites were studied by means of X-ray diffraction, Mossbauer spectroscopy and vibration sample magnetometer. X-ray diffraction studies revealed that not all samples have a single ferritic phase, a small second phase corresponding to BaTi6O13 was also observed to form. The Mossbauer spectra changed from magnetically ordered (x = 0) to magnetically ordered with strong line broadening. Moreover, the broadening increases with TiO2 content. The Mossbauer parameters suggested that Ti4+ occupies the 2a and 12k crystal sites, and the Ti4+ substitution on the 2b and 4f(2) site also occurs at high melt dopings. Therefore, coercivity and saturation magnetization decreased.