Structural and magnetic properties of SrFe12−2xTixRuxO19

Abstract

The magnetic properties of M-type Strontium hexaferrites can be modified by partially substituting Fe ions by other metallic ions. In this work, we report on the effect of the substitution of Ti2+ and Ru4+ ions for Fe3+ ions on the magnetic properties of the system, and the dependence of these properties on the cationic distribution in the lattice. SrFe12−2xTixRuxO19 hexaferrite samples were prepared by ball milling and sintering at 1100°C the appropriate amounts of the starting powders. The structural and magnetic properties of the fabricated samples were investigated using X-ray diffraction, SEM, Mössbauer spectroscopy, and vibrating sample magnetometry. It was found that Ti–Ru substitution improved the crystallinity of the prepared samples slightly, and did not influence the particle size appreciably. Mössbauer spectroscopy revealed that Ti2+ and Ru4+ ions substituted Fe3+ ions at the 4f2, (4f1+2a) and 2b sites for x values up to 0.2, and at the 12k site for x>0.2. The saturation magnetization increased up to x=0.2, and then decreased for higher x values, while the coercivity decreased monotonically, recording a reduction of 70% at x=0.3. The magnetic properties of the system were interpreted in terms of the distribution of Ti2+ and Ru4+ ions in the hexagonal lattice.