EFFECT OF MAGNETISM ON SUPERCONDUCTIVITY IN RARE-EARTH COMPOUNDS RENI(2)B(2)C

Spin-polarized first-principles density-functional electronic structur e calculations were performed for 73-atoms embedded clusters represent ing antiferromagnetic RENi(2)B(2)C (RE = Pr, Nd, Sm, Gd, Ho, Tm). A su bstantial difference in the extent of the exchange polarization of the conduction electrons between early and late rare-earth compounds is r evealed due to the reduced coupling between RE 4f and 5d electrons wit h increasing Z. This result is relevant to observed phenomena of coexi stence of superconductivity and magnetism in these compounds.