The absence of antiferromagnetic coupling and GMR effect in evaporated permalloy/Cu multilayers, in situ transport properties

Abstract Thermally evaporated (permalloy Ni 80 Fe 20 )/Cu multilayers were deposited on to quartz glass substrate, oxidised Si and etched Si wafers at room temperature and at 100 K. The samples were examined during an evaporation process by means of in situ conductance measurements whereas magnetisation, X-ray diffraction, atomic force microscopy and the cross-section electron transmission microscopy were performed ex situ to characterise our samples. Only a very small GMR effect was observed for samples deposited at RT and at 100 K. An absence of the antiferromagnetic coupling seems to result from the large interface roughness. Multilayers deposited at 100 K showed the existence of a highly topological disordered alloy-like structure formed during the deposition process.