Elastic Constants in Cupric Formate Tetrahydrate Single Crystals

Abstract

Ultrasonic wave velocities in Cu(HCOO) 2 ·4H 2 O single crystals were measured at room temperature and all of thirteen elastic stiffness constants of this monoclinic crystal were obtained. The directions of both the displacement and the energy flow in sound waves were calculated using the data obtained and the relations between the energy flow directions and the wave normals were discussed. The temperature dependences of the ultrasonic wave velocities and the anomalous absorption were also measured with the special care in the vicinity of the transition temperature.