ELASTIC PROPERTIES OF PURIFIED SINGLE-CRYSTALLINE RHODIUM

A short overview is given of experimental investigations of single-cry stalline rhodium which mainly focus on its elastic behaviour in the ul trasonic frequency range. In particular, temperature-dependent ultraso nic attenuation and sound-velocity measurements performed on a zone-re fined single crystal below ambient temperature are reported. The excep tional acoustic quality of the sample permits investigations of the ma gnetoacoustic properties as well as the determination of the elastic s tiffness coefficients over a broad frequency range with quite high acc uracy. Especially those experiments which are governed by the main obj ective to investigate the influence of the electronic subsystem on bot h the sound velocity and the attenuation derive much benefit from this fact. As expected, the comparative analysis of all stiffness coeffici ents reveals a strong shear rigidity, indicating crystal forces that a re strongly angular-dependent. These are not very reminiscent of ordin ary metals and probably give rise to the peculiar mechanical propertie s commonly known from the polycrystalline material. Detailed studies o f the temperature-dependent elastic moduli indicate that the electroni c band structure of rhodium has to be taken into account for a satisfa ctory description of the elastic behavior.