Crystal Structure and Physical Properties of Mg6Cu16Si7-type M6Ni16Si7, for M = Mg, Sc, Ti, Nb, and Ta

TL;DR

This study reports the synthesis, crystal structures, and physical properties of M6Ni16Si7 compounds with M = Mg, Sc, Ti, Nb, and Ta, revealing metallic behavior and paramagnetism but no superconductivity.

Contribution

It provides detailed structural and physical characterization of a new family of M6Ni16Si7 compounds with various metals, expanding understanding of their electronic and magnetic properties.

Findings

All compounds are metallic and non-superconducting.

Magnetization shows temperature-independent paramagnetism.

Mg6Ni16Si7 and Sc6Ni16Si7 exhibit enhanced low-temperature paramagnetism.

Abstract

Five compounds were investigated for magnetic character and superconductivity, all with non-magnetic nickel and band structures containing flat bands and steep bands. The syntheses and crystal structures, refined by powder X-ray diffraction, are reported for M6Ni16Si7, where M = Mg, Sc, Ti, Nb, and Ta. All compounds form in the Mg6Cu16Si7 structure type. Resistance measurements are also reported on M6Ni16Si7 (M = Mg, Sc, Ti, and Nb) down to 0.3 K, with all four showing metallic conductivity. No superconductivity is observed. Magnetization measurements for all compounds reveal essentially temperature independent paramagnetism, with a tendency toward more enhanced low temperature paramagnetism for the cases of Mg6Ni16Si7 and Sc6Ni16Si7.