PHASE-TRANSITIONS OF SPIN POLARIZED HE-3 - THERMODYNAMICAL NUCLEAR ORIENTATION TECHNIQUE

Completely polarized **3He behaves in many respects very differently from normal **3He. In principle, it can be obtained by purely thermodynamical methods, starting from a strongly polarized solid (by a magnetic field at very low temperature), as long as the overall experimental time is less than T//1, the magnetic relaxation time. The crucial points of such an experiment - dependence of liquid **3He energy on magnetization, value of T//1 - and the new experimental possibilities it opens are discussed. In particular, completely polarized **3He appears as the best chance to observe a vacancy solid phase, first described by A. Andreev and I. M. Lifshitz.