Dresden 2009 – scientific programme
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MA: Fachverband Magnetismus
MA 17: Magnetic Thin Films I
MA 17.8: Talk
Wednesday, March 25, 2009, 12:00–12:15, HSZ 04
Magnetoelectric phase transition in Fe/Cu(111) — •Lukas Gerhard1, Toyo K. Yamada1, Timofey Balashov1, Albert F. Takács1, Arthur Ernst2, and Wulf Wulfhekel1 — 1Physikalisches Institut, Universität Karlsruhe (TH), Germany — 2Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany
Both the crystallographic and the magnetic structure of Fe exhibit a rich phase diagram. Two different crystallographic phases, fcc and bcc, have been reported to coexist in Fe islands on Cu(111) [1]. Comparing our scanning tunnelling spectroscopy to ab-initio calculations, we identified the magnetic ordering of these two phases as layer-wise antiferromagnetic and ferromagnetic. Surprisingly, we observed transitions between these two phases during our STM measurements at 4 K. A systematic study of the tunnelling parameters revealed the electric field of the STM tip as the origin. Applying different electric fields, we could switch between the two different phases on nm scale. The observed coupling of the crystallographic and magnetic structure with an external electric field is explained by a difference in the work function of the two phases and thus evidences Fe/Cu(111) as a multiferroic system.
[1] A. Biedermann, W. Rupp, M. Schmid and P. Varga, Phys. Rev. B 73, 165418 (2006)