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 Tuesday Sessions
       Session MI+EL-TuM

Paper MI+EL-TuM3
Spin Wave Dynamics of Interacting and Non-interacting Magnetic Elements on the Sub-micrometer Scale

Tuesday, October 30, 2001, 9:00 am, Room 110

Session: Spintronics I: Magnetization Dynamics and New Materials
Presenter: S.O. Demokritov, University Kaiserslautern, Germany
Authors: S.O. Demokritov, University Kaiserslautern, Germany
J. Jorzick, University Kaiserslautern, Germany
B. Hillebrands, University Kaiserslautern, Germany
M. Bailleul, CEA Saclay, France
C. Fermon, CEA Saclay, France
K. Guslienko, Oakland University
A.N. Slavin, Oakland University
D. Berkov, Innovent Jena, Germany
Correspondent: Click to Email
Confinement caused by the lateral edges of small magnetic elements qualitatively changes dynamic properties of such elements. Instead of well-known spin wave bands, characteristic for thin magnetic films that are infinite in plane, one observes quantized spin wave modes with wavevectors determined by the element lateral sizes.@footnote 1@ Here we report a new highly localized spin wave mode in small magnetic elements. This mode was observed using Brillouin light scattering from thermal spin fluctuation in arrays of micrometer-size, 35 nm thick permalloy elements: rectangular dots and stripes magnetized perpendicular to their axes. The in-plane field 0.3-0.6 kOe was high enough to remove the remanence domains in the investigated elements. However, due to the non-elliptical shape of the elements the total saturation cannot be reached at any applied field. Domains (near the edges of the element that are perpendicular to the field) exist. The observed new mode is localized near those edge domains and has a frequency of 4-6 GHz depending on the applied field. The width of the localization region is much smaller than the lateral size of the element (< 200 nm). Due to high magnetic susceptibility in the region of the mode localization the mode amplitude caused by thermal fluctuation is much higher than that of the quantized modes. The experimental observation of a new mode is confirmed by a theoretical analysis, based on the solution of a non-local dipole problem, as well as by numerical simulations. If the distance between the elements in an array approaches a value comparable with their thickness, the dipole-dipole interaction between the elements becomes measurable. Due to this interaction the phase locking of the spin waves of neighboring elements takes place: spin fluctuations in different elements are correlated. Thus, a collective spin wave mode propagating through the array of magnetic elements is created. @FootnoteText@@footnote 1@J. Jorzick et al. Phys. Rev. B, 60 (1999) 15194.