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DS: Fachverband Dünne Schichten

DS 40: Magnetism in Thin Films: Interaction Phenomena and Heterostructures

DS 40.5: Vortrag

Freitag, 29. Februar 2008, 13:45–14:00, H 2032

Magnetic texturing of ferromagnetic films by sputtering induced ripple formation — •Hans Hofsäss¹, Kun Zhang¹, Michael Uhrmacher¹, and Johann Krauser² — ¹II. Physikalisches Institut, Universität Göttingen, 37077 Göttingen — ²Fachbereich Automatisierung und Informatik, Hochschule Harz, 38855 Werningerode

Ripple patterns created by sputter erosion of iron thin films induce a correlated magnetic texture of the surface near region. We investigated the magnetic anisotropy as a function of film thickness and determined the thickness of the magnetically anisotropic layer as well as the magnitude of the magnetic anisotropy using MOKE and RBS measurements. Ripple patterns were created by sputter erosion with 5 keV Xe ions at 80^∘ incidence with respect to the surface normal. For ion-fluences above 1x10¹⁶ cm⁻² ripples with wavelengths of 30 nm - 80 nm oriented parallel to the ion beam direction are observed. MOKE measurements reveal a uniaxial magnetic anisotropy of the surface region of the films with orientation parallel to the ripple orientation. The magnetic texture is confined to a 12+/-3 nm thick layer, in accordance with the average grain size. The magnetic anisotropy within this layer varies from 25% for thick films towards 100% for films with less than 30 nm thickness. The magnitude of the anisotropy is determined by the shape anisotropy of the rippled surface as well as the interface roughness. We have demonstrated that sputter erosion yields highly anisotropic magnetic thin films and can be used to fabricate nanorods and nanowires with pronounced uniaxial magnetic anisotropy.