The effect of the heat treatment on the magnetism, magnetocaloric effect and microstructure formation has been systematically studied in Fe-rich (Mn,Fe)y(P,Si) melt-spun ribbons (1.80 ≤ y ≤ 2.00). XRD, SEM and EDS measurements demonstrate that a metal deficiency prompts the stable (Mn,Fe)Si phase, whereas in the metal-rich region the (Mn,Fe)3Si phase is formed. It is found that the annealing temperature influences the composition and lattice parameters of the (Mn,Fe)y(P,Si) alloys, which greatly affects the Curie temperature (TC). For the optimal metal/non-metal ratio y the magnetic entropy change (|ΔSm|) is found to increase from 5.5 to 15.0 Jkg−1K−1 in a magnetic field change of 2 T by varying the annealing temperature from 1313 to 1433 K, indicating an enhancement of the first-order magnetic transition (FOMT). The presented results reveal that the secondary phase and magnetic properties in the (Mn,Fe)y(P,Si) system can be tuned by varying the annealing temperature and by adjusting the metal/non-metal ratio y.
- Magnetic properties
- Magnetocaloric materials