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MA: Fachverband Magnetismus

MA 11: Magnetic Thin Films I

MA 11.7: Talk

Tuesday, March 27, 2007, 11:45–12:00, H10

Magnetic superstructure in Fe/native Fe-oxide multilayers — •Sebastien Couet, Thomas Diederich, and Ralf Röhlsberger — Hamburger Synchrotron Strahlungslabor (HASYLAB) at Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607 Hamburg

It has been discovered recently that Fe/native Fe-oxide multilayers carry an anomalously high magnetic moment [1], the origin of which is not understood yet. We present here a study on the magnetic structure of such systems. Multilayer samples are prepared by repeated deposition of 2.3 nm of Fe and subsequent exposure to oxygen that forms a native oxide layer of about 1.6 nm. Using the isotope sensitive technique of nuclear resonant scattering of synchrotron radiation we are able to selectively probe the magnetic structure of the metallic Fe of the system. A non-collinear alignment is found between adjacent Fe layers coupled through the oxide spacer with a canting angle close to 90° in low fields. The measured magnetic field dependence shows that the spin system rotates as a rigid unit upon magnetization reversal while the coupling angle slowly decreases in high field. This behavior can be explained by a proximity magnetism model which implies an antiferromagnetically ordered oxide spacer layer [2].

[1] G.S.D. Beach et al., Phys. Rev. Lett. 91, 267201 (2003).

[2] J.C. Slonczewski, J. Magn. Magn. Mater. 150, 13 (1995).