ULTRATHIN METAL-FILMS BY DESIGN - EXPLOITING THE CLOSE CORRELATION BETWEEN STRUCTURE AND MAGNETISM

To design ultrathin metal films with desired properties, it is necessa ry to understand the close correlation between film structure and film properties. In this paper several examples of the relationship betwee n the magnetism and the structure of thin metallic films are presented . It is demonstrated that for iron films on Cu(100) and Cu3Au (100) an d for MnCu surface alloys, unusual film structures are often accompani ed by unusual magnetic properties. While two fee phases, which differ in their crystallographic and magnetic states, have been stabilized on Cu(100) depending upon film thickness, no fee modification is observe d on Cu3Au(100). This can be understood qualitatively if the different contributions to the total energy of the film are considered. For the weak magnets Mn and Fe studied here, this points towards a pronounced contribution of the surface to stabilizing unusual magnetic phases. T his is demonstrated even quantitatively for the Cu(100) c(2 x 2)Mn pha se, where an unusual surface-layer corrugation is accompanied by a lar ge magnetic moment. An improved understanding of the energies that gov ern the correlation between structural and magnetic properties should widen the opportunities for designing ultrathin films with desired mag netic characteristics.