Improved magnetic properties of Cr3+ doped SrFe12O19 synthesized via microwave hydrothermal route

Abstract Cr doped Sr-hexaferrites (SrCr x Fe 12− x O 19 ) were prepared using microwave-hydrothermal method and sintered at 950 °C/90 min using single mode microwave furnace. With increasing Cr 3+ content, the lattice parameters changed anisotropically, where ‘ a ’ increases and ‘ c ’ decreases. The average grain sizes of sintered hexaferrite are in the range of 280–660 nm. XPS spectra shows that for higher Cr 3+ content i.e., x > 0.3, both Fe 2+ and Fe 3+ ions are present in the crystal structure. With Cr 3+ doping saturation magnetization systematically decreased and coercivity increased. Magnetic hyperfine analysis using Mossbauer technique indicates that Cr 3+ ions preferentially occupy 2 a , 12 k , and 4 f 1 sites.