MOSSBAUER 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 degrees C for different times. The s amples were examined by thermomagnetic analysis, X-ray diffraction, ma gnetic and Mossbauer measurements. W-type single-phase compounds were obtained by heating the samples at 1320 degrees C but only polyphase m aterial was obtained after heating to 1100 and 1200 degrees C. The sam ples treated at 1320 degrees C for 5 h had the best intrinsic magnetic properties: sigma(s) = 89 +/- 1 emu/g, H-A = 13.8 kOe and T-C = 432 d egrees C. The Mossbauer spectra give evidence of a magnetic order, in agreement with a hypothesis of selective occupation by Zn2+ and Li+ ca tions of the tetrahedral and octahedral spin-down sublattices, respect ively.