Structural properties and oscillatory magnetoresistance of Co(hcp)/Cu sandwiches

Abstract

We present structural and magnetoresistance studies for a series of Co(hcp)/Cu sandwiches. RHEED patterns obtained during growth indicate a hcp structure for at least the first Co layer. NMR measurements show a single resonance peak at a frequency of 228 MHz, clearly confirming the hcp structure of both Co layers. The occurrence of the hcp phase for the Co atoms is mainly due to the growth of a thin 8 Å Cu seed layer on the Ru buffer layer. We performed magnetoresistance studies at room temperature and found oscillatory behaviour of the magnetoresistance with a period of about 13 Å, which is smaller than the values usually observed for fcc (111)Co/Cu systems. The magnetoresistance value at the first maximum reaches 4% at room temperature, which indicates the good quality of these samples.