Systematic Investigations of the Solid Solution Zr(V_1–<i>x</i>Al_<i>x</i>)₂ Adopting the Laves Phase Structures

Laves phases are an interesting field of research when it comes to structural chemistry and physical properties. Investigations of the ternary system Zr-V-Al showed, in contrast to the system Hf-V-Al, that no superstructures can be observed within the solid solution Zr(V_1-xAl_x)₂. High values of x form aluminum rich phases that adopt the hexagonal MgZn₂ type structure while low values of x lead to vanadium rich phases that adopt the cubic MgCu₂ type. All samples were investigated by powder X-ray diffraction experiments. Single crystal studies indicated that no superstructure formation is present in the investigated samples. ²⁷Al MAS NMR investigations confirmed these findings. For ZrAl₂, quantum-chemical calculations helped with the analysis of the ²⁷Al NMR spectrum of the binary endmember of the solid solution. Some of the prepared samples were investigated with respect to their magnetic properties. The investigated compounds show Pauli-paramagnetism, in Zr(V_0.875Al_0.125)₂ in addition superconductivity with a critical temperature of T_C=4.17(1) K was observed. Investigations of compositions that do not belong to the Laves phase regime clearly indicate that the MgZn₂ type structure is still the dominant phase. Regardless of the starting composition chosen, the hexagonal Laves phase was mostly present.