Crystallographic texture and interface structure in Co/Cu multilayer films

Abstract

This paper reports on the apparent relationship between giant magnetoresistance (GMR) and crystallographic texture in sputter-deposited polycrystalline Co/Cu multilayers. In agreement with previous work, we find that GMR decreases from a typical literature value in a randomly oriented multilayer to a very low value of less than 2% in multilayers with a strongly defined 〈111〉 fiber texture. The change in orientation and the retained integrity of the multilayer is followed by x-ray diffraction and reflectivity, and high-resolution electron microscopy and electron diffraction. Modeling of the x-ray reflectivity data suggests that there is no significant change in the interface roughness of the multilayers with change in texture. To complement the magnetic hysteresis and GMR measurements, the transition from partially antiferromagnetic coupling to ferromagnetic coupling has been followed by polarized neutron reflectivity with in situ magnetization measurements.