Speaker
Description
A. Sanz-Prada1, P. Álvarez-Alonso1,2, J.L. Sánchez Llamazares3, L. Escobedo3, J.S. Garitaonandia4, P. Gorria1,2, J.A. Blanco1 and J. López-García 1,2,
1 Department of Physics, Faculty of Science, University of Oviedo 33007, Spain.
2 Instituto Universitario de Tecnología Industrial de Asturias, Universidad de Oviedo, Gijón 33203, Spain.
3 Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055, Colonia Lomas 4ª sección, San Luis Potosí, S.L.P. 78216, México.
4Leioa, Spain
In recent years, magnetocaloric materials have demonstrated higher efficiency and greater environmental friendliness compared to conventional gas compression technologies. Intermetallic RFeSi compounds (where R denotes a rare-earth element) exhibit a second-order magnetic transition that depends on the ionic radius of the rare-earth element [1]. This transition occurs over a broad temperature range, approximately 20–150 K, making these materials suitable for low-temperature applications such as hydrogen liquefaction. They crystallize in a tetragonal structure with space group P4/nmm, where R and Si occupy the 2a Wyckoff positions and Fe occupies the 2c site [2]. However, conventional thermal treatments to achieve a single-phase structure are costly and time-consuming, often requiring up to 35 days at 1373 K. In this context, the melt-spinning technique emerges as a rapid and convenient approach to obtain single-phase, nanostructured materials.
In this study, we present a detailed investigation of the magnetic behavior and magnetocaloric properties of GdFeSi ribbons produced by melt spinning. X-ray diffraction on the as-cast ribbons reveals a preferred (001) orientation along the ribbon growth direction and confirms the nanometric size of the crystallographic grains. Combined neutron diffraction and Mössbauer spectroscopy analyses indicate that the magnetic order originates solely from the Gd ions, while the Fe magnetic moment is negligible or absent. Notably, the isothermal magnetic entropy change in GdFeSi ribbons shows a broadening, extending the temperature range over which significant entropy changes occur and enhancing the refrigerant capacity compared to bulk samples. These findings emphasize the potential of GdFeSi ribbons for low-temperature magnetocaloric applications and highlight the advantages of melt spinning in producing nanostructured materials.
Overall, the melt-spinning method allows the fabrication of high-quality, nanostructured GdFeSi ribbons with tunable magnetic and magnetocaloric properties, primarily governed by the magnetic ordering of the Gd sublattice.
Acknowledgements
This work has been partially supported by the following projects: (a) PTDC/EMETED/3099/2020, UIDP/04968/2020-Programático; (b) PID2022-138256NB-C21, from Spanish MCIN/AEI/10.13039/501100011033 and ERDF, UE; GRU-GIC-24-113, from SEKUENS, Principality of Asturias, Spain, and; (c)CF-2023-I-2143 from CONAHCYT, Mexico.
References
[1] H. Zhang, et al., J. Alloys and Compounds, 993 (2024) 174570.
[2] R. Welter, J. Alloys Compd., 189 (1992).