Berlin 2012 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 33: Magnetic Coupling Phenomena/ Exchange Bias

MA 33.5: Vortrag

Mittwoch, 28. März 2012, 16:15–16:30, EB 202

Structural and magnetic properties of the Fe layers in CoO/Fe/Ag(001) heterostructure — •Rantej Bali¹, Marcio Soares², Aline Ramos², Helio Tolentino², Fikret Yildiz¹, Clemence Boudot², Olivier Proux³, Maurizio De Santis², Marek Przybylski¹, and Jürgen Kirschner¹ — ¹Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany — ²Institut Néel, CNRS and Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9, France — ³Observatoire des Sciences de l’Univers - OSUG- Grenoble, F-38051 Grenoble, France

We elucidate the influence of interfacial oxidation on the magnetic behaviour of CoO/Fe grown on Ag(001) at 340 K. The Fe layer was in the form of a wedge from 0 to 10 monolayers (ML) thickness. Magneto-optic Kerr Effect (MOKE) and X-ray Absorption Near Edge Spectroscopy (XANES) were employed to obtain the Fe-thickness dependence of the magnetic and structural characteristics respectively. The interfacial region consists of a disordered Fe_1−xO_x layer with x varying from 0.6 at the interface to 0 in deeper Fe layers. The depth of Fe_1−xO_x formation depends on the Fe thickness prior to CoO coverage; from 0 to 4 ML Fe the whole depth forms the oxide. The depth of Fe_1−xO_x decreases linearly from 4 to 2 ML as Fe thickness increases from 4 to 8 ML above which the depth of Fe_1−xO_x remains constant. Correspondingly 4 ML of CoO covered Fe show zero magneto-optic signal and at 8 ML the largest exchange bias can be induced by zero field cooling. The results can be explained by considering the growth mode of Fe on Ag(001) and defects from the interfacial Fe_1−xO_x layer.