PRESERVED INTERFACIAL MAGNETISM AND GIANT ANTIFERROMAGNETIC EXCHANGE COUPLING IN CO RH SANDWICHES/

The interlayer coupling in Co/Rh/Co sandwiches prepared by UHV evapora tion has been investigated by means of magnetization and transport exp eriments. We found that the antiferromagnetic coupling strength for th in Rh layers is the largest ever obtained in magnetic systems, reachin g approximately 34 erg/cm(2) for 5 Angstrom thick Rh interlayer. This value is 7 to 8 times larger than the highest value previously observe d in the Co/Ru system prepared under similar conditions. This unexpect edly large difference in the coupling strength between these two syste ms is mainly due to the magnetic nature of the interfaces. This is fur ther supported by ab initio calculations of the magnetic moments in su perlattices with mixed interfaces.