Speaker
Description
Fe-based alloys, characterized by their unique nanocrystalline structure, exhibit remarkable soft magnetic properties such as high relative permeability ($>10^{5}$), high saturation magnetization ($>1.0$ T), low coercivity and almost zero magnetostriction [1], making them ideal candidates for a wide range of technological applications, such as transformer cores, inductors, and magnetic sensors. All of these exceptional magnetic properties arise from their unique microstructure characterized by ultrafine grains with a relatively narrow size distribution ($10-50$ nm), which are homogeneously dispersed in the residual amorphous matrix [2].
This article is devoted to the study of the Fe$_{73.5}$Cu$_{1}$Nb$_{3}$Si$_{15.5}$B$_{7}$ alloy and the correlation of its nanocrystalline microstructure with the resulting magnetic properties (mainly coercivity). Subtle changes in the microstructure were induced by a series of isothermal annealing with different annealing times and temperatures. These microstructural changes were investigated using X-ray diffraction, transmission electron microscopy, small-angle X-ray scattering and magnetic measurements. The magnetic properties of all series of isothermally annealed samples were investigated using Koerzimat, Mossbauer spectroscopy and ferromagnetic resonance. It is shown that a series of isothermal annealing causes subtle changes in the microstructure of the nanocrystalline material, which are visible in course of coercivity and by means of FMR measurements. SAXS proved to be a sensitive method for describing thermally induced changes in the microstructure (especially particle size and distribution) with respect to a wide range of length scales involved.
Acknowledgments
This study was funded by the EU NextGenerationEU through the Recovery and Resilience Plan for Slovakia under the project No. 09I03-03-V03-00034.
References
[1] P. R. Roach et al., “Spin structure of solid 3He below 1 mK neutron diffraction,” AIP Conference Proceedings, vol. 103. AIP, pp. 82–82, 1983. https://doi.org/10.1063/1.34214
[2] G. Herzer, “Nanocrystalline soft magnetic materials,” Journal of Magnetism and Magnetic Materials, vol. 157–158. Elsevier BV, pp. 133–136, May 1996. https://doi.org/10.1016/0304-8853(95)01126-9
