Patent ID: 8109100

Claim:
A process for preparing a material of general formula (I) comprising the following steps: (a) providing Co, Mn, Si, and optionally A, B and C, in amounts sufficient to produce a material of formula (I): [(A y Co 1-y )] u (Mn 1-z C z )[(Si 1-x B x )] v (I) wherein: A is selected from Ni, Cr, Fe, Al, P, Se, Ga and Sb and mixtures thereof; B is selected from Ge, Sn, Al, P, Se, Ga and Sb and mixtures thereof; C is selected from Ni, Cr, Fe, Al, P, Se, Ga and Sb and mixtures thereof; x, y and z are the same or different and are numbers in the range 0 to 0.2; and u and v are the same or different and are numbers in the range 0.5 to 1.5; (b) co-melting the metals provided in step (a) under an inert atmosphere; (c) cooling the mixture of molten metals; (d) annealing the material at a temperature of from 825 to 975° C.; (e) slowly cooling the material from step (d) to 825° C. or below; and (f) optionally, if the material from step (e) is above room temperature, further cooling the material to room temperature.