The elastic constants of chromium

Measurements have been made of the three single-crystal elastic stiffness constants of chromium from 4·2°K to 345°K using an ultrasonic pulse-echo technique. The compressional constants C 11 and C 12 show large anomalies at the antiferromagnetic Néel temperature T N=311°K, and much smaller anomalies at the spin-flip temperature, T SF=123°K. The shear constants C 11–C 12 and C 44 show rather small anomalies at T N but there are large changes at T SF. Between T SF and T N all the elastic constants are magnetic field dependent and the anomalous behaviour may be understood, in principle, in terms of a stress-induced movement of antiferromagnetic domain boundaries.