MAGNETIC-POLARIZATION OF THE PD SPACER AND INTERLAYER MAGNETIC COUPLINGS IN FE PD(001) SUPERLATTICES - 1ST PRINCIPLES CALCULATIONS/

This paper is devoted to a theoretical study of the magnetic propertie s of Fe/Pd superlattices. We mostly focus our attention on the determi nation of both the interlayer magnetic couplings (IMC) and the magneti c-moment distributions as a function of the Pd spacer's thickness. We use an ab initio method (augmented spherical wave) to determine self-c onsistently the electronic structure, the magnetic-moment distribution s, and the total energies for the considered systems. We consider two model structures for the Pd spacers (1) a fct structure for which the Pd atoms keep their bulk atomic volume and (2) a fcc structure for whi ch the Pd atomic volume is expanded. For the first structure, the magn etic polarization in the palladium spacer is limited mostly to the fir st three monolayers near the Fe-Pd interfaces and the IMC are similar to the ones obtained for nonmagnetic spacers. The IMC decrease rapidly with an oscillating behavior. On the contrary, for the second atomic structure, the whole Pd spacer is polarized with a moment of about 0.1 5mu(B)/atom for n less-than-or-equal-to 14 (n being the number of Pd a tomic layers) and the IMC are ferromagnetic in a large range of Pd thi cknesses. We present a detailed study of (i) Fe3Pd1 superlattices whos e ground state is shown to be antiferromagnetic and (ii) the polarizat ion induced in the Pd spacer in relation with the current theoretical models.