AVS 45th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Thursday Sessions
       Session MI-ThA

Paper MI-ThA2
Experimental and Model Theoretical Dispersions of Unoccupied Metallic Quantum Well States in Cu/fccCo/Cu(100) and Related Systems

Thursday, November 5, 1998, 2:20 pm, Room 324/325

Session: Structure & Magnetism of Surfaces & Interfaces
Presenter: A.G. Danese, Rutgers University
Authors: A.G. Danese, Rutgers University
F.G. Curti, Rutgers University
R.A. Bartynski, Rutgers University
Correspondent: Click to Email
The dispersion with parallel momentum (k @sub ||@) of unoccupied metallic quantum well (MQW) states in the Cu/fccCo/Cu(100) system has been measured using inverse photoemission and modeled using a phase accumulation approach. For Cu films in the 2 - 4 monolayer range, a state close to the Fermi level is observed to have a flat dispersion near the neck of the Cu Fermi surface along the @GAMMA@-BAR X-BAR direction of the two dimensional Brillouin zone. Appearance of this state coincides with a hybridization gap in the Co minority spin bands. The calculation shows that the large effective mass of this state is the result of the rapid change in the scattering phase shift across the gap. The periodicities with which MQW states cross the Fermi level at the center and at the neck of the Cu Fermi surface, which correspond to the long and short period oscillatory magnetic coupling in this system, are well reproduced by the calculation. Furthermore, the observed phase shift of the short period magnetic coupling when the ferromagnetic layer is changed from Fe to Co to Ni layers can be attributed to changes in the position of this hybridization gap with respect to the Fermi level across this series. The effect of this behavior on the strength of the short period magnetic coupling in these systems is discussed.