Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Spin structures and Magnetic Phase Transitions
MA 15.4: Vortrag
Dienstag, 1. April 2014, 10:15–10:30, HSZ 403
Magnetic transitions in Mn/Ag(111) — •Jingfan Ye, Franziska Lambrecht, Timofey Balashov, and Wulf Wulfhekel — Physikalisches Institut, Karlsruhe Institute of Technology, Wolfgang-Gaede-Str. 1, 76131 Karlsruhe, Germany
An antiferromagnetic manganese monolayer on Ag(111) exhibits a 120∘-Néel structure due to geometric frustration [1]. Using a spin-polarized scanning tunneling microscope, we investigated the ground state of Mn islands on Ag(111) of sizes between 10 and 10000 nm2 at 4K. We found out that the magnetic contrast disappears below a certain island size. In an intermediate region, it was also possible to observe switching between different configurations of the Néel state, at a rate scaling linearly with an externally applied magnetic field. We attribute the observed effects to a quantum phase transition, in which the anisotropy barrier between the classical ground states is lowered with decreasing island size and increasing magnetic field [2].
[1] C.-L. Gao et al. Phys. Rev. Lett. 101, 267205 (2008)
[2] P. Legett et al. Rev. Mod. Phys. 59, 1-85 (1987)