Internal-friction anomalies in crystalline hydrogen
Leont'eva A. V., Marinin G. A., Anisimova T. N.
Anomalous features have been detected in the low-frequency internal friction in crystalline n-H2 at low temperatures. These features are peaks at T~5.5 and 9 K, an increase in the internal-friction background at T< 8 К with decreasing temperature, and a low and relatively constant shear modulus in the interval 2-12.5 K. The features seen in the low-frequency internal friction in hydrogen which are also seen in solid argon are attributed to an increase in the mobility of defects at low temperatures.