MAGNETIC AND MAGNETOTRANSPORT PROPERTIES OF PD-BASED SUPERLATTICES

We present the results of magnetic and magnetotransport measurements on (100) Fe/Pd superlattices. Samples with Fe layer thicknesses almost-equal-to 20 angstrom and Pd layer thicknesses in the range 10-40 angstrom were fabricated by molecular beam epitaxy, using (100) MgO substrates with a 200 angstrom buffer layer. The structure of the multilayers was characterized by RHEED, X-ray diffraction and TEM. SQUID magnetization measurements at various Pd thicknesses reveal a strong polarization of the Pd layers in contact with the Fe, and the presence of a weak oscillatory interaction which suggests an interlayer exchange coupling between Fe layers. In particular, antiferromagnetic-like coupling is seen at 15 K for a palladium thickness around 30 angstrom. Magnetoresistance measurements on samples in the same range of Pd thicknesses show a small spin-valve effect (almost-equal-to 3%).