Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 53: Spin Structures at Surfaces and in thin films II

MA 53.5: Vortrag

Freitag, 4. April 2014, 10:30–10:45, BEY 118

Electric-field induced magnetic anisotropy on the atomic scale — •Andreas Sonntag, Jan Hermenau, Anika Schlenhoff, Johannes Friedlein, Stefan Krause, and Roland Wiesendanger — Institute of Applied Physics, University of Hamburg, Germany

One of the challenges in data storage applications is the control of magnetic anisotropy: To stabilize a magnetic bit against thermal magnetization reversal a large anisotropy is needed, while a low anisotropy is desired when writing information. A device employing electric fields to actively reduce the magnetic anisotropy during writing could benefit from smaller power consumption compared to conventional devices.

In our experiments we investigate the impact of an electric field onto the anisotropy of individual atomic-scale magnets. The superparamagnetic switching of uniaxial Fe magnets on W(110) [1] is studied using spin-polarized scanning tunneling microscopy (SP-STM). Electric fields up to 6 GV/m are applied at very low tunnel current, thereby excluding current induced effects. The experiments show that the electric field E can be used to increase or decrease the switching rate, depending on the sign of E. This is attributed to an electric-field induced anisotropy that favors in-plane magnetization for E < 0 and out-of-plane magnetization for E > 0. The interpretation of this concept is verified by changing from an in-plane to an out-of-plane system.

Our experiments demonstrate magnetic manipulation without exploiting spin or charge currents, thereby opening the pathway towards electric-field based spintronic applications on the atomic scale.

[1] S. Krause et al., Phys. Rev. Lett. 103, 127202 (2009).