Berlin 2015 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 48: Magnetization / Demagnetization Dynamics IV
MA 48.1: Vortrag
Donnerstag, 19. März 2015, 15:00–15:15, EB 301
Magnetic reversal and magnetization dynamics in artificial ferromagnetic quasicrystals — •Vinayak Bhat1,2, Barry Farmer2, Lance DeLong2, Joseph Sklenar3, John Ketterson3, and Justin Woods2 — 1Technical University of Munich, Munich, Germany — 2University of Kentucky, Lexington, USA — 3Northwestern University, Evanston, USA
Studies on ferromagnetic (FM) antidot arrays, i.e. arrays of non-magnetic regions in an otherwise continuous FM thin film, so far have been restricted to periodic lattices [1]. We have fabricated artificial FM quasicrystals (AFQs) in the form of connected networks of nanostructured Permalloy segments on five-fold rotationally symmetric (but aperiodic) Penrose P2 tilings (P2Ts) [2]. Low-field DC magnetization curves M(H,T) indicate abrupt transitions between ordered magnetization textures, and novel "asymmetric" ferromagnetic resonance modes are found to exist on only one side of the field origin accompanying "knee" anomalies in M(H,T). We argue that AFQs behave also as novel artificial spin ice systems that exhibit non-stochastic switching, pinned Dirac monopoles, and Dirac strings due to their aperiodicity and inequivalent pattern vertices.
We acknowledge support by the Custer of Excellence Nanosystems Initiative Munich.
[1] S. Neusser et al., Adv. Mater. 21, 2927 (2009). [2] V. S. Bhat et al., Phys. Rev. Lett. 111, 077201 (2013).