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MA: Fachverband Magnetismus

MA 52: Poster II

MA 52.32: Poster

Donnerstag, 15. März 2018, 15:00–18:00, Poster C

Magnetic properties of the Fe_xNi_8−xSi₃ materials, 0≤ x ≤8 — •Mohammed Ait Haddouch¹, Simone Gallus², Jörg Perßon¹, Jörg Voigt¹, Karen Friese¹, and Andrzej Grzechnik² — ¹Jülich Centre for Neutron Science-2/Peter Grünberg Institut-4, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — ²Institute of Crystallography, RWTH Aachen University, Jägerstr. 17-19, 52066 Aachen, Germany

In this work, the magnetic properties of the system Fe_xNi_8−xSi₃ with 0≤ x ≤8 were investigated by DC magnetization measurements for 1≤ x ≤6 in the temperature range from 10 K to 900 K. The system features a large number of different crystallographic sites for the magnetic ions, which is a possible ingredient for good magnetocaloric materials. Within the ternary Fe_xNi_8−xSi₃ system, two different stability fields have been observed [1]. For the Ni₃₁Si₁₂ structure types samples with 0≤ x ≤4 we find magnetic transitions below 380 K evidenced by sudden changes in the slope of the M(T) curves. Even above these temperatures, the samples do not exhibit Curie-Weiss behavior, indicating the existence of another magnetically ordered phase. For 5≤ x ≤8 samples with the Fe₃Si structure type with compositions exhibit only one phase transition around 800 K. On the basis of our data, a magnetic phase diagram will be proposed over the full range of Fe_xNi_8−xSi₃ compositions between 0 K and 900 K. We will also derive the magnetic entropy change for the different magnetic transitions of these compound, to check their magnetocaloric effect efficiency.

[1] Gallus et.al, submitted to Solid State Sciences, (2017)