IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Magnetic Interfaces and Nanostructures Thursday Sessions
       Session MI-ThP

Paper MI-ThP7
On the Origin of the Thickness-dependent Dimensional-crossover in Ultrathin Magnetic Films

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Magnetic Thin Films & Surfaces Poster Session
Presenter: N.A.R. Gilman, Penn State University
Authors: N.A.R. Gilman, Penn State University
M. Hochstrasser, Lawrence Berkeley National Laboratory
R. Zhang, Penn State University
R.F. Willis, Penn State University
Correspondent: Click to Email
We report experimental results that show that the order parameter @beta@, which determines the long-range (spin) ordering in magnetic thin films (M=M@sub o@(1-T/Tc)@super beta@), changes abruptly due to a crossover in dimensionality at different thicknesses in Ni(100), Ni(110) and Ni(111) films. We argue that the different critical thicknesses arise from finite-size quantization energies of the (spin) excitations, which are dependent on the magnitude of associated wavevectors spanning different crystallographic directions of the fcc Fermi surface. Experimental data on nickel alloys support this view.