Topics in Physics of Superfluid HELIUM(3) Films.

A study has been made of the dipolar and magnetic orientational effects in two-dimensional superfluid ('3)He films. The stable phases are found and the continuous -wave nuclear magnetic resonance spectrum (cw NMR) has been calculated for these phases. Two thickness regimes are considered: thickness comparable to the interparticle separation, and thickness much larger than the interparticle separation but smaller than the superfluid coherence length. The form of the dipole Hamiltonian is found to be similar for both regimes, but numerical differences in coefficients of various terms in some cases lead to qualitatively different results. Remarkable differences exist in the NMR spectrum of the two phases of interest (Anderson-Brinkman-Morel and Balian-Werthamer types of states) and two thickness regimes. From the results of the calculation it follows that the cw NMR is an excellent diagnostic tool for the pairing state in films, as it is in the bulk. I have also studied quantum size effects in thin (thickness less than the coherence length but much larger than the interparticle separation) films of superfluid ('3)He. For this thickness, quantum size effects are most prominent, while several theoretical simplifications are possible. The Gorkov equations for the p-type superfluid are solved in the parallel-plate geometry assuming specularly reflecting walls. A simple decomposition of the pairing potential is used which allows explicit evaluation of the various thermodynamic quantities and the NMR response in the ABM state. The transition temperature is monotonically depressed as the thickness decreases and exhibits only weak oscillatory behavior. On the other hand, the shift in the transverse resonance frequency shows characteristic discontinuous jumps. Particular emphasis is placed on the experimentally detectable deviations from the bulk behavior. The effects of surface roughness are briefly discussed.