Connection between giant magnetoresistance and structure in molecular-beam epitaxy and sputtered Fe/Cr superlattices

We have performed a comparison of magnetoresistance and structure of epitaxial and textured Fe/Cr superlattices grown by molecular-beam epitaxy (MBE) and magnetron sputtering with either (110) and (100) orientations on a variety of substrates. MBE samples grown along the (100) orientation, exhibit narrower rocking curves (mosaic spread) and lower saturation resistivities than sputtered samples. On the other hand, (110) MBE and sputtered samples have comparable saturation resistivities. The magnetoresistance (Delta rho) of MBE and sputtered samples are comparable. Epitaxial MBE samples, with small rocking curves, show a clear correlation between the magnetoresistance and rocking curve width. In sputtered samples, roughness, controlled by the deposition pressure, plays an important role although the general trends depend on orientation and mosaic spread of the samples.