Ternary rare earth transition-metal Laves phases are a rich family of intermetallic compounds with the general formula RTX (R = Rare earth elements, T = transition metals, X = non-metals). These systems have been studied extensively and their investigations have led to the discovery of new materials with a variety of physical properties, e.g., large magnetocaloric effect, large magnetoresistance, and superconductivity. These compounds crystallize in three structure types: cubic MgCu2, hexagonal MgZn2, and hexagonal MgNi2. The structures of the ternary Laves family depends strongly on the influence of the valence electron concentration (VEC) of the T element. For instance, one could observe all three structure types in one system, GdTAl, with decreasing VEC of the T element (T = Ni, Cu–MgNi2; Co, Fe–MgZn2; Mn–MgCu2). The valence electron concentration determines not only the crystallographic structure but also the magnetic properties of these compounds. The TC increases with decreasing VEC of the T element (TC = 66 K for Ni and 275 K for Mn). To systematically investigate the effect of VEC on the structure and magnetic properties of GdTAl, we have synthesized the Ti–Cr analogs. Herein, we will present their structural and magnetic properties and compare them to their late-transition-metal counterparts (Mn–Cu).

Varying the fermi level in gadolinium transition-metal aluminides

2019 Fall National Meeting

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