EFFECTS OF INTERCALATION OF LITHIUM ION ON SUPERCONDUCTIVITY OF YNI2B2C

Cyclic voltammograms indicate that the Li+ ions can be electrochemical ly intercalated into and deintercalation from the crystal lattice of Y Ni2B2C reversibly. Measurements of the ac susceptibility show that the superconductivity becomes worse when the amount of the intercalated l ithium ions exceeds 1.0 per primary unit of YNi2B2C and completely dis appears as it reaches 1.5 per unit. X-ray photoelectron spectroscopy ( XPS) spectra imply that the electronic structure near the Y-C plane pl ays an important role in the superconductivity of YNi2B2C.