Josephson-like tunneling behaviour of polarized neutron wave-particles and possibilities of measuring very large penetration depths by polarized neutron reflectometry

It is shown that the tunneling of polarized neutron wave-particles offers new possibilities for the investigation of surface diamagnetism in superconductors. As an example, a thin film Fabry-Perot resonator of natural vanadium sandwiched between two isotopical vanadium 50 thin films in the Meissner state, under total reflection, is considered. This method allows the possibility of measuring strong magnetic penetration depths up to 45000 A. The related sensitivity to penetration depth ratio ΔΛ/Λ and the external magnetic field is of the order of 1 permille and 1.2 G respectively. ((orig.))