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+NS-ThM

Paper MI+NS-ThM8
Photoemission Electron Microscopy and X-Ray Magnetic Circular Dichroism of Ultrathin FeNi Alloy Films on Cu(111)

Thursday, November 1, 2001, 10:40 am, Room 110

Session: Magnetic Imaging and Spectroscopy
Presenter: Y. Sato, University of California, Davis
Authors: Y. Sato, University of California, Davis
T.F. Johnson, University of California, Davis
S. Chiang, University of California, Davis
F. Nolting, Lawrence Berkeley National Laboratory
A. Scholl, Lawrence Berkeley National Laboratory
X.D. Zhu, University of California, Davis
D.P. Land, University of California, Davis
Correspondent: Click to Email
We are studying the system of NiFe/Cu(111) to understand and control the surface/interface magnetism relevant to the application of the giant magnetoresistive effect to magnetic recording heads. We used the Photoemission Electron Microscope (PEEM2) at the Advanced Light Source to observe the domain structures of the alloy films. PEEM has the unique capability of imaging the film's magnetic structure with high spatial resolution and elemental specificity. Element specific magnetic contrast images and X-ray Magnetic Circular Dichroism (XMCD) spectra were obtained for eight different samples of varying Fe compositions at two different thicknesses. Samples with higher Fe content (x = 0.66, 0.74) were non-magnetic at room temperature. This trend of reduction in Curie temperature at higher Fe concentration agrees both with our XMLD data on the same system@footnote 1@ and with previous work on FeNi/Cu(100).@footnote 2@ We speculate this is a structure-driven effect related to the "Invar effect" in the bulk alloy. The PEEM images clearly show that Fe and Ni form a good alloy and have the same domain structures with their magnetization aligned. Further, we find a strong thickness and concentration dependence of the magnetic domain structures. For 5ML films, the domain structures appear to be strongly influenced by surface topography of the substrate. For 10ML films, however, the effect of the substrate features is already insignificant. At this thickness, the Fe concentration is also found to affect the size of the domains and the presence of an easy magnetization axis. @FootnoteText@ @footnote 1@T.F.Johnson, S.Chiang, Y.Sato, et al., to be published @footnote 2@F.O.Schumann, S.Z.Wu, G.J.Mankey and R.F.Willis Phys.Rev.B 56, 2668 (1997).