COEXISTENCE OF MAGNETISM AND SUPERCONDUCTIVITY IN EPITAXIAL GDN W/NBN/W(100) AND RELATED NBN/W(100) MULTILAYERS/

The magnetic and superconducting properties of epitaxial, (100)-orient ed GdN/W/NbN/W multilayers have been characterized. We find that the i nterfacial layer of W permits the GdN/NbN layers to be grown smoothly. We report large flux trapping effects in the magnetic hysteresis loop s measured below the superconducting transition temperature (T-c) of t he multilayer, indicating the coexistence of magnetism and superconduc tivity down to layer thicknesses of 40 and 22 Angstrom for the NbN and GdN, respectively. Nonmagnetic NbN/W multilayers were also studied; i n these multilayers, T-c is enhanced considerably above that of a sing le NbN layer due to coupling of the superconducting layers across the W spacers. This behavior is fitted to a model which explicitly include s interlayer coupling. [S0021-8979(98)04014-6].