MEASUREMENT OF PRINCIPAL MICROSTRUCTURE AND MAGNETIC PROPERTIES OF DOPED Ba FERRITE PARTICLES

Anna Grusková - Jozef Sláma - Alvaro González Angeles - Martin Šoka

   The magnetic and structural properties of substituted M-type Ba hexaferrites with composition BaFe_12-2x(Me₁Me₂)_xO₁₉ were prepared and studied. Divalent Me₁ = Ni, Zn, Sn and tetravalent Me₂ = Ru, Zr, Ti, Sn ionic combinations were used in various compounds. The phase purity of the samples was evaluated by temperature dependence of initial susceptibility χ(T) and specific saturation polarisation J_s-m(T) and it was verified by Mossbauer spectroscopy. Mossbauer studies revealed that Ru⁴⁺, Zr⁴⁺, Ti⁴⁺ replaced the Fe³⁺ ions in distinct sites. The Ni²⁺, Zn²⁺ and Sn²⁺ occupation sites were identified as well. Strong drop of ΔH_c(x) near x = 0.1 and slight decrease of ΔH_c(x) close to x = 0.3 for (NiRu)_x and (ZnRu)_x leads to the conclusion that the reached value of ŁGHc corresponds to planar anisotropy. The particles of all the ferrite samples exhibit a plate-like, nearly hexagonal shape with the diameter under 100 nm.

Keywords: Hexagonal ferrites, substitution effect, magnetic properties, magnetic susceptibility, Mössbauer spectra

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