ELECTRONIC ASPECT AND GIANT MAGNETORESISTANCE IN CO CU/CO SANDWICH STRUCTURES/

We have studied the electronic states in a non-magnetic spacer layer o f Co/Cu/Co sandwich layers using the magneto-optical Kerr effect (MOKE ) and x-ray photoemission and have found that they are discrete owing to the quantum size effect and appear approximately every 10.6 +/- 0.5 Angstrom. This coincides with the oscillation period of the saturatio n field. We connect them with the quantum minority-spin interface stat es near the Fermi level E(F) The magnetoresistance found in these sand wich layers has been calculated on the basis of the quantum size effec t transport theory with the requirement that there exist quantum well states within individual layers or groups of layers. The results of th e calculation and experiments have been discussed.