EPJ Web of Conferences 40, 06008 (2013)
https://doi.org/10.1051/epjconf/20134006008

Hard magnetic properties of melt-spun Mn-Al-C alloys

¹ SATIE, ENS Cachan, CNRS, UniverSud, 61 av President Wilson, F­94235 Cachan, France
² Wigner RCP, HAS, ISSPO, H­1525 Budapest, POB 49, Hungary

Abstract

Structural and magnetic characterization of Mn_x−yAl_100−x−yC_2y (x = {50, 55}; y = {0, 1}) melt­spun ribbons is reported. To obtain the metastable ferromagnetic τ­phase, rapidly solidified alloys were annealed either in a vacuum furnace at 823 K or directly in the vibrating sample magnetometer under applied magnetic field. Optimal magnetic properties were demonstrated by Mn₅₄Al₄₄C₂ samples proved to be single­phase with a coercivity of 0.19 T measured in both cases. For this composition the structural ε→τ phase transformation has been magnetically detected at 786 K, Curie temperature of τ­phase (T_c = 592 K, T_p = 610 K) has been determined using mean field approximations in ferromagnetic and paramagnetic regions. Rietveld refinement of X­ray diffraction spectra was employed to analyse the phase constitution of annealed alloys, lattice parameters as a function of chemical composition and mean grain size for the phases involved.