AVS 50th International Symposium
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI+NS-TuM

Paper MI+NS-TuM9
Magnetic Linear and Circular X-ray Dichroism Studies of the Magnetic Instability of Fe(x)Ni(1-x) Pseudomorphic Thin Films Exhibiting the Invar Effect

Tuesday, November 4, 2003, 11:00 am, Room 316

Session: Magnetic Imaging and Magnetic Spectroscopies
Presenter: S.A. Morton, Lawrence Berkeley National Laboratory
Authors: S.A. Morton, Lawrence Berkeley National Laboratory
M. Hochstrasser, Lawrence Livermore National Laboratory
N.A.R. Gilman, Pennsylvania State University
R.F. Willis, Pennsylvania State University
G.D. Waddill, University of Missouri - Rolla
J.G. Tobin, Lawrence Livermore National Laboratory
Correspondent: Click to Email
At a composition of 65% Fe, bulk Fe(x)Ni(1-x) alloys exhibit the invar effect: a sudden change in the atomic volume which is associated with a dramatic change in the magnetic ordering from a high-spin high-volume state to a low-spin low-volume state at higher Fe concentrations; this results in a collapse in the magnetic moment and Curie temperature. Magnetic X-ray Linear Dichroism measurements of the Fe and Ni 3p exchange splitting have been used as a probe of the element specific Fe and Ni magnetic moments for ultra thin fcc FeNi/Cu(100) films across the full compositional range. These results have been further complemented by composition dependent Magnetic X-ray Circular Dichroism measurements of the element specific orbital and spin moment contributions. The data shows excellent agreement with published neutron and SQUID magnetometry measurement and with theoretical predictions of the Fe and Ni atomic moments based upon the 2gamma state model and the Slater Pauling Curve. Furthermore, the data demonstrate the potential for the use of magnetic linear dichroism as a quantitative element specific magnetometer in a wide variety of magnetic thin film systems.