AB-INITIO STUDY OF THE INTERLAYER MAGNETIC COUPLINGS IN FE PD(001) SUPERLATTICES AND OF THE POLARIZATION-INDUCED IN THE FE AND PD LAYERS/

In this paper we present a theoretical study of the magnetic propertie s of Fe(m)Pd(n)(001) superlattices, (m and n being the number of Fe an d Pd atomic layers). Our attention is mostly focused on the determinat ion of both the interlayer magnetic couplings and the magnetic moments distributions as a function of the Fe layer's and Pd spacer's thickne sses. We use an ab initio LSDA method (ASW) to determine self-consiste ntly the electronic structure, the magnetic moment distributions, and the total energies for the considered systems. For studying the role o f the Pd spacer's structure, we consider two model structures for the Pd spacers (i) a fct structure for which the Pd atoms keep their bulk atomic volume, and (ii) a fcc structure for which the Pd atomic volume is expanded. For the first structure, the magnetic polarization in th e palladium spacer is limited mostly to the Fe-Pd interfaces, and the couplings are similar to the ones obtained for nonmagnetic spacers. On the contrary, for the second atomic structure, the whole Pd spacer is polarized with a moment of about 0.15 mu(B)/atom for n less-than-or-e qual-to 14, and the couplings are ferromagnetic in a large range of Pd thicknesses. We present a detailed study of FemPd1 and Fe3Pdn superla ttices to determine both the couplings and the polarization induced in the Fe and Pd layers.