Dresden 2014 – scientific programme

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MA: Fachverband Magnetismus

MA 45: Spin Structures at Surfaces and in thin films I (Skyrmions)

MA 45.3: Talk

Thursday, April 3, 2014, 15:30–15:45, BEY 118

Temperature-driven phase transition of Fe/Ir(111) nanoskyrmions — •Stefan Krause, Andreas Sonntag, Jan Hermenau, and Roland Wiesendanger — Institute of Applied Physics, University of Hamburg

Skyrmions are topologically protected field configurations with particle-like properties. They are in the focus of many ongoing investigations due to their potential application for future spintronic devices. Using spin-polarized scanning tunneling microscopy (SP-STM) at low temperature (T=11 K), a lattice of nanoskyrmions has been shown to be the ground state of the one-atomic-layer thick Fe/Ir(111) surface [1].

In our recent SP-STM studies we investigated the influence of temperature onto the Fe/Ir(111) nanoskyrmionic lattice. The experiments reveal that the lattice is stable against thermal agitation up to T≈ 27.4 K. Further elevating T to 28.0 K results in a fading of the magnetic SP-STM contrast, indicating a phase transition into the paramagnetic state. By repeatedly varying T we elaborate a very sharp phase transition at T≈ 27.7 K. At second monolayer Fe step edges the skyrmionic lattice is found to persist even to higher T, which is attributed to pinning.

The experimental results will be presented and discussed in terms of magnetic corrugation amplitude of the skyrmion lattice and pinning decay length.

[1] S. Heinze et al., Nat. Phys. 7, 713 (2011).