QUANTUM VORTEX MELTING IN NB CUMN MULTILAYERS

We have measured the electrical resistance R vs temperature T in diffe rent perpendicular magnetic fields on Nb/CuMn multilayers. The samples had constant Nh layer thickness (similar to 230 Angstrom) and CuMn la yer thicknesses in the range 4-50 Angstrom. Below the zero-field super conducting critical temperature T-c, the (InR vs 1/T) curves showed a sharp change in the slope at magnetic-fieid-dependent temperatures T( H). The T vs H curves are consistent with vortex-lattice melting, mai nly due to quantum fluctuations.