LOW-TEMPERATURE PROPERTIES OF NUCLEAR-SPIN RELAXATION IN INORGANIC GLASSES

The temperature and frequency dependence of nuclear spin relaxation has been investigated for different nuclear probes in a large variety of inorganic glasses between 1. 5 K and room temperature. Below about 200 K, the data can be interpreted consistently in the framework of thermally-activated excitations of disordered modes (two-level-systems; TLS). The analysis demonstrates the common properties of the TLS in all the glasses. Low-temperature frequencies of the TLS excitations were found indicating that a TLS arises probably from a group of atoms.