Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 94: Spin-Dependent Transport Phenomena I (organized by MA)
TT 94.7: Vortrag
Donnerstag, 19. März 2015, 11:00–11:15, H 0112
Higher order contributions to Anisotropic Interface Magnetoresistance (AIMR) in Ni/Pt thin films — •Afsaneh Farhadi, André Kobs, Gerrit Winkler, Carsten Thönnißen, and Hans Peter Oepen — Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg, Jungiusstr. 11a, 20355 Hamburg, Germany
The influence of interfaces on the magnetotransport in systems with one ferromagnetic layer has attracted much attention. In Pt/Co/Pt the resistivity behaves as ρ(ϕ,θ) = ρt + Δρipcos2ϕsin2θ + Δρopcos2θ where ϕ/θ is the angle between magnetization and current direction/film normal [1]. While Δρip is caused by the conventional AMR (bulk effect) a Δρop∝ 1/t behavior was found for Pt(5nm)/Co(t)/ Pt(3nm) sandwiches revealing that Δρop originates at the Co/Pt interfaces (anisotropic interface magnetoresistance (AIMR)). So far the AIMR was observed also for Py/Pt and Co/Pd [2,3]. In order to answer the question if interfacial MR contributions also exist when stacking isoelectronic materials we investigated Ni/Pt systems. We prepared Pt(5nm)/Ni(t)/Pt(3nm) sandwiches with Ni thicknesses of 1−50 nm by dc magnetron sputtering on Si3N4 substrate. As a result, in contrast to previous findings, the ρ(θ) behavior can only be satisfactorily described when considering higher orders in the expansion of the MR up to n = 3: ρ(θ)= ρt + ∑n Δρop,2ncos2nθ. The thickness dependence of the amplitudes Δρop,2n behaves according to 1/t revealing that also the higher orders have their origin at the Ni/Pt interfaces. [1] A. Kobs et al., PRB 90, 016401 (2014), [2] Y.M. Lu et al., PRB 87, 220409 (2013), [3] J.-C. Lee et al., JAP 113, 17C714 (2013).