AMORPHOUS MAGNETISM IN FE-B ALLOYS - 1ST-PRINCIPLES SPIN-POLARIZED ELECTRONIC-STRUCTURE CALCULATIONS

We present self-consistent spin-polarized electronic-structure calcula tions for amorphous FexB100-x (50 less-than-or-equal-to x less-than-or -equal-to 95) alloys, based on a supercell linear-muffin-tin-orbital t echnique and realistic structure models produced by molecular-dynamics simulations. We show that the electronic densities of states of the a morphous alloys are very similar to that of the crystalline Fe borides . This confirms the conclusions as to the similarity of the local orde r in the crystalline and amorphous phases drawn on the basis of the st ructural studies. The calculated composition dependence of the magneti c moments is in good agreement with experimental data on amorphous fil ms, with a maximum of the magnetic moment close to 15 at. % B. The dec rease of the moment for lower B content is shown to arise from the com petition between ferro- and antiferromagnetic exchange interactions, t he decrease with higher B content is due to a dilution effect: polariz able d-d bonds are replaced by magnetically inert p-d bonds. We also p resent detailed calculations of the photoemission intensities.