Phase relations and magnetic properties of MM [CO_1-xCu_x]50 ≤ × ≤ 1 and MM[Co_1-xFe_x]50 ≤ × ≤ 0.3 alloys

Abstract

A systematic study of the effect of substitution of Cu in MM[Co_1-xCu_x]50 leq × leq 1and Fe in[MM Co_1-xFe_x]50 leq × leq 0.3 were made. The Cu substitution for Co gives stable CaCu₅ type phase in the entire composition range. The lattice parametersunderline{a} andunderline{c} of the 1:5 phase increase linearly with increasing Cu content. Fe has only a limited solid solubility in the 1:5 phase. For MM[Co_1-xCu_x]5 alloys the 4piM_{s} decreased from 95 e.m.u. g^-1 at x=0 to about 3 e.m.u. g^-1at x=1 while for MM[Co_1-xFe_x]5 alloys it increased to 101 e.m.u. g^-1 at x=0.1. A detailed phase composition of the alloys at 900°C and 700°C and the effect of Cu on the Tc of the 1:5 phase are also reported.