Experimental study of the surface properties of superfluid and normal He-3by plasma resonance of Wigner solid

A new experimental method has been developed for using plasma resonance of Wigner solid (WS) for the study of liquid He-3 surface properties in superf luid and normal states. The behaviour of optical coupled plasmon-ripplon (C PR) resonances have been investigated in magnetic field 15 mT at temperatur es down to 0.35 mK. The position of transverse optical plasma mode, which b ecomes visible when weak magnetic field is applied gives the information ab out WS coupling with helium surface. The line width of CPR resonance is use d for getting the collision time in the scattering of surface electrons fro m the surface roughness. The influence of the superfluid transition on the collision time is observed. (C) 2000 Elsevier Science B.V. All rights reser ved.