Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 22: Surface Magnetism (Joint Session with O)
MA 22.7: Talk
Tuesday, March 21, 2017, 11:30–11:45, HSZ 401
B-T phase diagram of Pd/Fe/Ir(111) — •Marie Böttcher1,2, Bertrand Dupé1,2, Jairo Sinova2, and Stefan Heinze1 — 1University of Kiel, Germany — 2University of Mainz, Germany
Skyrmions are localized and chiral non-collinear magnetic structures, which could be used as bits in data storage devices [1]. Such a device would require the stabilization and manipulation of skyrmions at room temperature. Recently, skyrmions have been stabilized and manipulated at 4.2 K in Pd/Fe/Ir(111) ultra-thin film [2]. Density functional theory calculations showed that skyrmions are stabilized by the competition between the Dzyaloshinskii-Moriya and the exchange interaction beyond the first nearest neighbor as well as the anisotropy [3, 4]. This competition can result in a spin glass behavior that has to be treated accordingly in Monte Carlo simulations. We performed parallel tempering Monte Carlo (PTMC) simulations [5] in order to calculate the B-T phase diagram of Pd/Fe/Ir(111). We identified order parameters that characterize the spin spiral, the skyrmion lattice and the isolated skyrmion phases. The calculated critical temperatures are in good agreement with previous calculations [4]. PTMC offers also the possibility to create and delete metastable skyrmions. Moreover, we used PTMC to calculate the chemical potentials of skyrmions and antiskyrmions at different magnetic fields, which indicates the possible creation of net topological charge. [1] A. Fert et al., Nat. Nanotech. 8 (2013). [2] N. Romming et al., Science 341 (2013). [3] B. Dupé et al., Nat. comm. 5 (2014). [4] L. Rózsa et al., Phys. Rev. B 93 (2016). [5] K. Hukushima et al., Phys. Soc. Jap. 65 (1996).