ELASTIC CONSTANTS AND ULTRASONIC ATTENUATION OF A BETA-TUNGSTEN-STRUCTURE V3GE CRYSTAL FROM 4.2 TO 300DEGREES K

The longitudinal and transverse acoustic velocities and the ultrasonic attenuation of a -tungsten V3Ge crystal with the -tungsten structure have been measured by a pulse technique at a frequency of 10 MHz between 4.2 and 300°K. The room-temperature elastic moduli have been determined as C11=2.966, C44=0.6978, and C12=1.042 in units of 1012 dyn/cm2. Contrary to the behavior of the -tungsten-structure compounds V3Si and Nb3Sn, the adiabatic compressibility of V3Ge was found to be temperature-dependent. The elastic constant C12 exhibits a lattice-softening phenomenon in the temperature interval between 75 and 300°K. The shear modulus 12(C11-C12) displays a minimum at 75°K. At this temperature the longitudinal (in contrast to the shear) attenuation shows a sharp peak. The behavior of the elastic moduli and attenuation is discussed in terms of possible operation of an electron transfer mechanism. In addition, both the longitudinal and the shear attenuation behave anomalously at 168°K. A relaxational process is assumed. The limiting value of the Debye temperature is found to be 487°K. At room temperature, it is 471°K. © 1969 The American Physical Society.