SUPERCONDUCTIVITY OF FERROMAGNETIC Fe- AND Co-BASED AMORPHOUS ALLOYS CONTAINING DISPERSED Pb AND Pb-Bi PARTICLES.

A new type of Fe- and Co-based alloy with an amorphous phase containing fine fcc Pb or hcp epsilon (Pb-Bi) plus bct X(Pb-Bi) plus Bi inclusions has been produced by melt quenching of Fe-P-Pb, Fe-P-Pb-Bi, Co-Si-B-Pb and Co-Si-B-Pb-Bi alloys containing immiscible elements Pb and Bi and have been found to exhibit superconductivity combined with ferromagnetism. The uniform dispersion of fine particles was achieved in each composition range below about 6 at % Pb and 7 at % (Pb plus Bi). The saturation magnetization at 4. 2 K was 159 J T** minus **1 kg** minus **1(emu/g) for (Fe//0//. //8P//0//. //2)//9//5Pb//3Bi//2 and 92 emu/g for (Co//0//. //7//5Si//0//. //0//8B//0//. //1// 7)//9//5Pb//3Bi//2. The transition temperature T//c was 7. 4K for (Fe//0//. //8P//0//. //2)//9//5Pb//5, 8. 6K for the Fe-P-Pb-Bi alloy, 7. 1K for Co//0//. //7//5Si//0//. //0//8B//0//. //1//7)//9//5Pb//5, and 8. 7K for the Co-Si-B-Pi-Bi alloy. The upper critical field at 4. 2K and the critical current density at zero applied field and 4. 2K were 1. 60T and 1. 25 multiplied by 10**7Am** minus **2 for the Fe-P-Pb-Bi alloy and 1. 72T and 1. 39 multiplied by 10**7Am** minus **2 for the Co-Si-B-Pb-Bi alloy.