High-Magnetic-Field Behavior of the Nuclear Spin Pressure of Solid ³He

Abstract

Much of the low-temperature behavior, particularly the ordering of the nuclear spins, in solid ³He is determined by a sizable exchange energy J. Hence solid ³He provides a unique system for studying the exchange energy and associated nuclear spin ordering effects. In order to gain more information about the nature of the exchange interaction and to make comparisons between theory and experiments, one has two options. The measurements can be extended down to the critical region T _c ≃ 3|J|/k ≃ 2 m°K, or one can, as suggested by Goldstein,¹ make measurements on the solid in the presence of strong magnetic fields at temperatures somewhat higher than T _c . The latter situation is in some ways more tractable experimentally.

Work supported in part by the National Science Foundation.