AVS 47th International Symposium
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI+NS+NANO 6-TuM

Paper MI+NS+NANO 6-TuM7
Magnetic Force Microscopy of Coupled and Decoupled Micrometer Scale Permalloy Structures

Tuesday, October 3, 2000, 10:20 am, Room 206

Session: Magnetic Imaging I
Presenter: U. Memmert, University of Saarbrücken, Germany
Authors: U. Memmert, University of Saarbrücken, Germany
A.N. Müller, University of Saarbrücken, Germany
U. Hartmann, University of Saarbrücken, Germany
J. Jorzick, University of Kaiserslautern, Germany
C. Krämer, University of Kaiserslautern, Germany
S.O. Demokritov, University of Kaiserslautern, Germany
B. Hillebrands, University of Kaiserslautern, Germany
E. Sondergard, CEA Saclay, France
M. Bailleul, CEA Saclay, France
C. Fermon, CEA Saclay, France
Correspondent: Click to Email
The magnetic structure and the magnetization reversal process of arrays of micron size rectangular magnetic permalloy islands were investigated by magnetic force microscopy in external magnetic fields. The samples were prepared by e@super -@-beam lithography and ion etching of UHV deposited 35 nm thick permalloy films. Islands of 1 µm x 1.75 µm dimensions were investigated with inter-island spacings between 0.1 µm and 1 µm. The data show a transition from not interacting islands for large inter-island spacing to interacting islands for the smallest spacing. For not interacting islands flux-closure structures were found to be present without external fields. Either a simple Landau structure with one single cross-tie within in the 180° wall or diamond structures consisting of 90° walls were found. For interacting islands the individual structures were often found in a magnetized state even in zero field. Edge domains were present on both short edges of each structure. A demagnetization of the interacting islands in an ac-magnetic field along the longer axis of the islands leaves the individual structures in a magnetized state with edge domains. Within the rows along the long island axis all structures are magnetized in the same direction. The rows show a row by row alternating magnetization resulting in a net zero magnetization for the entire sample. A demagnetization in an ac-field perpendicular to the long axis leaves each individual structure in a individually demagnetized state. Magnetization reversal for external fields along the long island axis takes place by simultaneous switching of structures being located together in the same row within the pattern.