Czechoslovak Journal of Physics vol:46 pages:2009-2010
We report on the transport properties of MBE-grown epitaxial Cr/Ag/Cr trilayers on MgO(001) substrates. The Ag thickness varies between 20 and 100 nm, the Cr thickness is 2-8 nm. The structures were characterized by RHEED, X-ray diffraction and atomic force microscopy. Compared to single Ag films of the same thickness, the positive magnetoresistance (PMR) at 4.2K is enhanced by one to two orders of magnitude, up to 120% in a field of 8 Tesla. This effect is slightly dependent on field and current orientation and disappears for T>100K. The MR curves measured at different temperatures demonstrate a scaling behaviour typical for transport in two-dimensional systems. The giant PMR is in a drastic way modified by the electron scattering at the Ag surface due to the presence of the seed and cap Cr layers.