Growth and some properties of Cr 11Ge 19

Abstract

Cr 11Ge 19 belongs to a large family of materials known as the Nowotny chimney-ladder compounds, some of which were recently proposed as advanced thermoelectric materials, particularly because of their low thermal conductivity related to their relatively complex crystal structure. In order to assess the potential of the compound Cr 11Ge 19 for thermoelectric applications, we grew large single crystals of this peritectic compound by a vertical gradient freeze technique and measured the thermoelectric properties of the crystals. Cr 11Ge 19 forms peritectically at 1201 K and crystals were grown from Ge-rich solutions. The conditions and the results of the crystal growth experiments are presented. The crystals were characterized by X-ray diffractometry, Laue technique, and electron probe microanalysis. The results of the thermoelectric property measurements suggest that Cr 11Ge 19 has a metallic behavior and therefore presents little interest for thermoelectric applications.