Giant Magnetoresistance of (001)Fe/(001)Cr Magnetic Superlattices

We have studied the magnetoresistance of (001)Fe/(001)Cr superlattices prepared by molecularbeam epitaxy. A huge magnetoresistance is found in superlattices with thin Cr layers: For example, with $t_{\mathrm{Cr}}=9\mathrm{}$ Å, at $T=4.2\mathrm{}$ K, the resistivity is lowered by almost a factor of 2 in a magnetic field of 2 T. We ascribe this giant magnetoresistance to spin-dependent transmission of the conduction electrons between Fe layers through Cr layers.