Structure redetermination, transport and thermal properties of the YNi3Al9 compound

Abstract

Single crystals of completely ordered variant of the YNi3Al9 compound were grown by self-flux method with excess of aluminum. The crystal structure of the title compound was redetermined from single crystal X-ray diffraction data. The structure adopts ErNi3Al9 type, space group R32, parameters of the unit cell a ​= ​7.2838(2) Å, c ​= ​27.4004(8) Å. The growth of relatively large single crystals of the YNi3Al9 compound, having completely ordered structure, indicates possible existence of region on phase diagram, where the title compound is in equilibrium with liquid. Comparison with the results in the literature on the investigations of the same and related compounds shows trend towards formation of more ordered structures in flux grown samples and more disordered ones in arc melted samples.Physical properties of the title compound - electrical resistivity, magnetoresistance and heat capacity - were measured for the first time. It shows metallic-like behavior with very high values of magnetoresistance up to 420% at low temperatures without presence of magnetic elements. Therefore electronic structure calculations were carried out. The phonon heat capacity reveals major Debye and minor Einstein contributions at the intermediate temperatures, and total heat capacity approaches Dulong-Petit limit at high temperatures. The calculated Debye temperature from the whole temperature range θD ​= ​480(6) K is typical for aluminium-rich compounds. Corresponding Einstein temperature is θE ​= ​198(8) K. The estimations of electron-phonon coupling constant λ ​= ​0.092 show very weak coupling and absence of superconducting transition.