Synthesis and characterization of Co-Ti-Sn alloys: Co1.5TiSn as half-metal based on the Fe1.5TiSb layered Heusler prototype

Abstract

The Co-Ti-Sn family of alloys from their half- to full-Heusler compositions are synthesized. Co1.5TiSn, a compound predicted by our theoretical calculations, is successfully synthesized in the L21 structure with cobalt vacancies in the tetrahedral sites. The saturated magnetic moment at 5 K is measured to be ~ 0.6 μB∕formula unit, consistent with density functional theory (DFT) predictions of half-metallicity in the compound. A cluster expansion-based analysis of the alloy system indicates the Co1.5TiSn compound to be nearly on the convex hull, within DFT accuracy. Our experimental realization of the Co1.5TiSn compound suggests that it is either kinetically or entropically stabilized.