Effects of rare earth additions on GMR of melt-spun Cu-Co-Ni ribbons

The effects of Ni and rare earth (La, Ce, Nd, Dy, Tb) co-addition on GMR of the melt-spun Cu-Co alloys are investigated. The results indicate that Ni addition can increase the GMR of the melt-spun Cu-Co ribbons. The reasons a re that Ni addition can restrain the liquid phase separation occurring at h igh temperature and increase the density of the fine magnetic Co-rich preci pitates during the annealing process. Light rare earth, such as Ce and La, can further enhance GMR of the melt-spun Cu-Co-Ni ribbons. Among these elem ents, Cc is the most effective. However, heavy rare earth additions result in a GMR decline of the melt-spun Cu-Co-Ni ribbons. It is discovered that t here exists an optimal addition quantity for Cc. Excessive Ce addition coul d result in a GMR decline as well. The reasons for the GMR improvement of R e addition are: role of purifying melt, promoting precipitates process and enhancing the magnetic susceptibility of the fine Co-rich precipitates. (C) 2001 Elsevier Science B.V. All rights reserved.