A series of Co2−x Ru x MnSi (x = 0, 0.25, 0.5, 0.75, 1) Heusler compounds were successfully synthesized. The heat-treatment conditions were crucial to make the materials form a single phase with a Heusler structure. With increasing Ru content, the half-metallic gap, lattice parameters and magnetization are continuously adjustable in a wide range. The Co2−x Ru x MnSi (x = 0, 0.25) compounds are rigorous half-metals and show a T 3 dependence of resistance at low temperature. The Co2−x Ru x MnSi (x = 0.5, 0.75, 1) Heusler compounds are the nearly half-metallic materials and show a semiconductive dependence of resistance at low temperature. The experimental magnetization is consistent with that in theory and follows the Slater–Pauling rule. The Curie temperature is higher than 750 K for all Co2−x Ru x MnSi Heusler compounds.

The paper reports on the effect of substituting Mn for Fe on the magnetostrictive and related properties of Fe 81−x Mn x Ga 19 alloys. Samples of composition were prepared in polycrystalline form and were all single phase BCC. It is shown that the magnetostriction observed in Fe 81 Ga 19 can be enhanced up to about 11% by Mn substitution with a maximum effect at x = 8. The change in the magnetostrictive coefficient of Fe 81 Ga 19 with Mn substitution is accompanied by a monotonic increase in resistivity, being increased by almost a factor of 2 for x = 8. We also found that the lattice parameter of the alloys increased with the increase in Mn concentration and the Curie temperature decreased monotonically at the same substitution.