Nuclear spin-lattice relaxation in bulk and divided samples of solid3He at low temperatures

✍ Scribed by R. P. Giffard; J. P. Stagg; W. S. Truscott; J. Hatton

• Publisher: Springer US
• Year: 1978
• Tongue: English
• Weight: 968 KB
• Volume: 31
• Category: Article
• ISSN: 0022-2291
• DOI: 10.1007/bf00116053

✦ Synopsis

At temperatures in the region of O. 1 K, the nuclear spin-lattice relaxation in solid 3He exhibits some unusual features which suggest that the mechanism might be diffusion in the spin system to surfaces within the crystal at which relaxation takes place rapidly. The results of a number of measurements of the diffusion of magnetization in solid 3 He specimens, including the influence of magnetic field, are presented. Relaxation time measurements on specimens formed in sintered glass give results consistent with the diffusion hypothesis, and for such specimens we can calculate the relaxation time and its magnetic ]ieM dependence with surprising accuracy. Similar calculations applied to bulk specimens, however, fail to account for the observations. The evidence suggests that the relaxation process in bulk specimens is not controlled by diffusion. An empirical formula is proposed which fits the relaxation data in bulk specimens over a range of parameters, although no physical process with the required properties can be identified.