Ultrasonic velocity measurements on potassium chrome alum

The velocity of propagation of longitudinal sound waves in a single crystal of potassium chrome alum was measured as a function of temperature. The waves were propagated normal to the (1,1,1) plane. In the temperature interval studied, from 300°K to 83°K, there were no discontinuities in the velocity within the limits of accuracy of the data. The velocity at 83°K showed only a slight increase (less than 3%) over the room temperature value. The effect of a magnetic field at right angles to the direction of propagation of the waves was investigated from 300°K to 92°K. Magnetic fields of approximately 2100 gauss had no effect on the velocity of propagation