Magnetic moments of Ni clusters Article uri icon

abstract

  • We have calculated the average magnetic moments per atom (Formula presented) of nickel clusters (Formula presented) as a function of cluster size in the range (Formula presented). The cluster geometries have been taken from molecular-dynamics simulations with a semiempirical many-body potential for (Formula presented), and for (Formula presented) the same potential was used for a steepest-descent relaxation of icosahedral structures. The spin-polarized electronic structure has been calculated for those optimized geometries with a self-consistent tight-binding method considering the (Formula presented), (Formula presented), and (Formula presented) valence electrons. The results are discussed in comparison with recent experimental data and other theoretical calculations. The theory explains perfectly the magnetic moments up to (Formula presented) and the decreasing tendency of (Formula presented) with cluster size. With respect to the oscillations of the measured magnetic moment for larger (Formula presented), the theory gives an explanation for the minima, which appear to be associated with an icosahedral growth pattern. The observed maxima are more difficult to reproduce and we discuss some plausible alternatives. © 1998 The American Physical Society.

publication date

  • 1998-01-01