Oscillation period of the interlayer coupling for epitaxial Fe/Cr1-xVx(100) and (211) superlattices

The microscopic origin of the 18 Angstrom period in the oscillatory interla yer exchange coupling of Fe/Cr(100) and (211) superlattices is investigated by alloying the Cr spacer with V to alter its Fermi surface. The addition of V increases or decreases in size the various Fermi surface calipers that are candidates for governing the oscillation period, such as those that sp an the ellipse, lens, octahedron, and nested sheets. Epitaxial sputtered su perlattices of (100) and (211) orientation were grown and characterized via magnetoresistance measurements as a function of spacer layer thickness for different V-doping levels. A small decrease of the oscillation period is f ound experimentally which strongly implicates the N-centered ellipse as the origin of the 18 Angstrom period in Fe/Cr superlattices. (C) 1999 American Institute of Physics. [S0021-8979(99)67908-7].