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Magnetization and room temperature Mössbauer studies of 50Fe2O3–50SiO2 and 90Fe2O3–10SiO2 ceramic fibers processed by laser floating one method
Authors: A. Salehizadeh, N.M. Ferreira, M.A. Valente, B.F.O. Costa
Ref.: Hyperfine Interact 241, 19 (2020)
Abstract: In this work, we employed the Laser Floating Zone (LFZ) method to grow the ceramic fibers with composition of 50Fe2O3-50SiO2 and 90Fe2O3-10SiO2, with two different pulling rates: 25 and 200 mm/h. The physical properties of the ceramics were studied as the function of the iron oxide content and the pulling rate. XRD analysis depicted that the main crystalline phase formed in all samples is magnetite. Although, the appearance of small quantity of nano-crystalline fayalite was also confimed. From the magnetic measurements, a Verwey transition for all LFZ fibers in the temperature range varying from 100 to 115 K depending on the composition and the pulling rate, was observed. Room temperature 57-Fe Mössbauer measurements showed that the degree of non-stoichiometry of LFZ ceramics with 90% of the iron content is higher than one for LFZ samples containing 50% of iron oxide. A great agreement was obtained between the result of Mossbauer spectroscopy measurements and VSM studies. The revealed behaviours can be described in terms of the temperature dependent interactions occurring between the magnetic clusters formed in the fibres.
