Magnetic Properties of Divalent (Ni,Sn,Zn)- Tetravalent (Ru,Sn) Ionic Mixtures of Substituted Ba Ferrite

The drop of coercivity, while preserving the saturation magnetic polarisation $J_{S}$ of substituted M-type Ba hexaferrites with composition $BaFe_{12-2x}(Me_{1}Me_{2})_{x}O_{19}$, was studied. Divalent $Me_{1}$=Ni, Zn, Sn and tetravalent $Me_{2}$=Ru, Sn ionic combinations were used in various compounds. Mössbauer spectroscopy was used to reveal sites of replacement of the $Fe^{3+}$ ions by $Ru^{4+}$ and $Sn^{4+}$. The $Ni^{2+}$, $Zn^{2+}$ and $Sn^{2+}$ occupation sites were identified as well. Strong drop of coercivity difference Δ $H_{c}(x)$ near x=0.1 and slight decrease of Δ $H_{c}(x)$ close to x=0.3 was obtained for suitable coupling of $Me_{1}^{2+}$ and $Me_{2}^{4+}$ ions.