Mössbauer and magnetic study of Sr (ZnLi0.5Fe0.5) Fe16O27 hexaferrite

A W-type hexagonal ferrite of composition Sr(ZnLi0.5Fe0.5)Fe16O27 has been prepared by ceramic technique using ball milling followed by heat treatment at 1100, 1200 and 1320°C for different times. The samples were examined by thermomagnetic analysis, X-ray diffraction, magnetic and Mössbauer measurements. W-type single-phase compounds were obtained by heating the samples at 1320°C but only polyphase material was obtained after heating to 1100 and 1200°C. The samples treated at 1320°C for 5 h had the best intrinsic magnetic properties: ?s = 89 ± 1 emu?g, HA = 13.8 kOe and TC = 432°C. The Mössbauer spectra give evidence of a magnetic order, in agreement with a hypothesis of selective occupation by Zn2+ and Li+ cations of the tetrahedral and octahedral spin-down sublattices, respectively.