Strong ferromagnetism at the surface of an antiferromagnet caused by buried magnetic moments.
Carrying a large, pure spin magnetic moment of 7 μB per atom in the half-filled 4f shell, divalent europium is an outstanding element for assembling novel magnetic devices in which a two-dimensional electron gas may be polarized due to exchange interaction with an underlying magnetically-active Eu layer. Here we show that the Si-Rh-Si surface trilayer of the antiferromagnet EuRh2Si2 bears a surface state, which exhibits an unexpected and large spin splitting controllable by temperature. The splitting sets in below ~32.5 K, well above the ordering temperature of the Eu 4f moments (~24.5 K) in the bulk, indicating a larger ordering temperature in the topmost Eu layers. The driving force for the itinerant ferromagnetism at the surface is the aforementioned exchange interaction. Such a splitting may also be induced into states of functional surface layers deposited onto the surface of EuRh2Si2 or similarly ordered magnetic materials with metallic or semiconducting properties.
1] Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany [2] St. Petersburg State University, Ulyanovskaya street 1, St. Petersburg 198504, Russia.
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Chikina
1] Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany [2] Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
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Höppner
Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, D-01187 Dresden, Germany.
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Seiro
European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, Boite Postale 220, F-38043 Grenoble, France.
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Kummer
Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
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Danzenbächer
Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
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Patil
Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
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Generalov
Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
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Güttler
1] Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany [2] Institute for Metal Physics, National Academy of Sciences of Ukraine, Vernadsky blvd. 36, UA-03142 Kiev, Ukraine.
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Kucherenko
1] Donostia International Physics Center (DIPC), Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, 20080 San Sebastian, Spain [2] Tomsk State University, Lenina Av., 36, 634050 Tomsk, Russia.
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Chulkov
1] Tomsk State University, Lenina Av., 36, 634050 Tomsk, Russia [2] Institute of Strength Physics and Materials Science of Siberian Branch Russian Academy of Sciences, pr. Akademicheskii, 2/4, 634021 Tomsk, Russia.
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Koroteev
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Koepernik
Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, Helmholtzstr. 20, P.O. Box 270116, D-01171 Dresden, Germany.
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Köpernik
Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, D-01187 Dresden, Germany.
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Geibel
Swiss Light Source, Paul Scherrer Institut, Aarebrücke, CH-5232 Villigen, Switzerland.
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Shi
1] Swiss Light Source, Paul Scherrer Institut, Aarebrücke, CH-5232 Villigen, Switzerland [2] SwissFEL, Paul Scherrer Institut, Aarebrücke, CH-5232 Villigen, Switzerland.
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Radovic
Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
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Laubschat
1] Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany [2] St. Petersburg State University, Ulyanovskaya street 1, St. Petersburg 198504, Russia.
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Vyalikh