Large positive magnetoresistance in Cr/Ag/Cr trilayers

Large positive magnetoresistance (LPMR) effects have been measured at temperatures T < 100 K in epitaxial Cr/Ag/Cr trilayers grown by molecular beam epitaxy. Compared to single Ag films, the magnetoresistance at 4.2 K is enhanced by nearly two orders of magnitude reaching values up to 120% in a field of 8 Tesla. This behavior is related to a drastic modification of the electron scattering at the Ag interfaces due to the presence of the buffer and cap Cr layers. The LPMR curves measured at different temperatures demonstrate a scaling behavior typical for electron transport in two-dimensional systems. The magnitude of the LPMR is a function of temperature and residual resistance ratio and is influenced by the direction of the applied magnetic field. (C) 1997 American Institute of Physics.