Magneto-crystalline properties of BaFe12−2x M x Sn x O19 (M = Sn, Ni, Zn) ferrite powders

Abstract

BaFe 12−2x M x Sn x O 19 compounds, where M=Sn 2+ , Ni 2+ or Zn 2+ ions, were synthesized by mechanical milling and partially by citrate precursor methods. Analysis of magneto-crystalline structure has been carried out by Mössbauer spectroscopy. The Sn 4+ ions replace Fe 3+ ions on 2b and slightly on 2a+4f 1 sites, Zn 2+ ions strongly prefer 4f 1 sites, Sn 2+ ions prefer 4f 1 sites too and Ni 2+ ions occupy 4f 2 and 12k or 2a sites. The magnetic properties were evaluated by the vibrating sample magnetometry and the thermomagnetic analysis. A large variation of the intrinsic coercivity H c (330 to 78 kA/m) and of temperature coefficient of coercivity of ΔH c /Δϑ (0.39 to 0.22 kA/m°C) were achieved as a function of the (Zn-Sn) and (Sn-Sn) substitutions, respectively. The Curie temperature T c decreased with the (Ni-Sn) substitution from 447 to 399°C.