THE COEXISTENCE OF SUPERCONDUCTIVITY AND FERROMAGNETISM IN (CE1-XGDX)RU2 - SELF-INDUCED VORTEX STATE

Electric resistivity, ac magnetic susceptibility, magnetization and **1**5**7Gd NMR measurements have been performed in the title compound for x equals 0. 12 and 0. 13. The resistivity measurement determines the superconducting transition temperature for x equals 0. 12 and 0. 13 to be 4. 85 K and 4. 4 K, respectively, though both the susceptibility and magnetization show no diamagnetism. An internal field associated with the ferromagnetic order appears in **1**5**7Gd NMR, where the nuclear spin-lattice relaxation time for x equals 0. 12 below 100 mK shows a characteristic temperature dependence for the superconductivity. From these results, it is concluded that the compound with x equals 0. 12 is microscopically in a coexistent state of the superconductivity and the ferromagnetism at low temperature, forming a self-induced vortex state.