RELATION BETWEEN INTERFACE ROUGHNESS AND GIANT MAGNETORESISTANCE IN MBE-GROWN POLYCRYSTALLINE FE CR SUPERLATTICES/

We have studied the influence of the interface roughness on the giant magnetoresistance (GMR) of polycrystalline Fe/Cr superlattices, grown by molecular beam epitaxy on polycrystalline substrates. The interface quality was changed systematically by varying the growth temperature between 0 and 400-degrees-C and by the use of a Cr seed layer. X-ray-d iffraction spectra, combined with resistivity data, show that a modera te step density at the interfaces can enhance the GMR, whereas interdi ffusion and important interface roughness strongly suppress the GMR.