Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 1: Magnetic nanoparticles (joint session MA/CPP)

MA 1.2: Vortrag

Montag, 12. März 2018, 09:45–10:00, H 0112

Non-coherent reversal of magnetization in single Pt/Co/Pt nanodots with diameter below 100nm — •Eva-Sophie Wilhelm, Stefan Freercks, Philipp Staeck, Carsten Thönnißen, and Hans Peter Oepen — Center for Hybrid Nanostructures, Universität Hamburg, Germany

We investigate magnetization reversal behavior of single Pt/Co/Pt nanodots with a diameter of 35nm and a Co thickness of 1nm using anomalous Hall-effect magnetometry [1] at temperatures from 2.5K to 270K. The samples were fabricated from polycrystalline films by electron beam lithography and ion milling.

For nanodots with uniaxial anisotropy and a diameter below 100nm single domain behavior and coherent rotation reversal according to the Stoner-Wohlfahrt model is expected [2] [3]. However non-coherent switching with two jumps in the hysteresis is observed for some of the dots with out-of-plane magnetization at low temperatures. Comparison of the reversal of two different dots from the same film material and micromagnetic simulation using Mumax3 [4] gives hints that this finding is caused by different local magnetic properties of the initial films. The differences presumably originate from the distribution of grains of different crystal orientation in the nanodots. Funding by DFG via SFB 668 is gratefully acknowledged. [1] A. Neumann et al. Nano Letters. 13, p2199-2203, (2013) [2] A. Neumann, Ph.D thesis, Universität Hamburg, (2015) [3] E. C. Stoner and E. P. Wohlfarth, Philos. Trans. R. Soc. London, Ser. A 240, 599 (1948) [4] A. Vansteenkiste et al. AIP Advances 4 107133 (2014)