THERMOMECHANICAL EFFECT IN NORMAL LIQUID-HE-3 WITH NONMAGNETIC BOUNDARY SCATTERING

The thermomechanical effect in normal liquid He-3, confined in a porou s plug pre-plated with 4 He-4 non-magnetic monolayers, has been measur ed. A previous experiment showed that there is a thermomechanical effe ct (analogue of thermoelectricity) but only when the 3He is confined i n pores with d much less than l, where d is the pore size and l the bu lk 3He quasiparticle mean free path. The effect was large, an order of magnitude larger than a theoretical determination by Edwards, Culman and He. This was possibly a magnetic scattering anomaly; we therefore repeated the experiment with the pre-plated porous plug, with dramatic ally different results. In the d much less than l limit, below 5 mK, w e find dP/dT similar to S/6, compared with the theoretical S/3, where S is the entropy per unit volume.