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Hybrid spintronic structures with magnetic oxides and Heusler alloys

DOI: 10.1109/TMAG.2008.2002188 DOI Help

Authors: Y. B. Xu (University of York) , S. S. A. Hassan (University of York) , P. K. J. Wong (University of York) , J. Wu (University of York) , J. S. Claydon (University of York) , Y. X. Lu (University of York) , C. D. Damsgaard (Technical University of Denmark) , J. B. Hansen (Technical University of Denmark) , C. S. Jacobsen (Technical University of Denmark) , Y. Zhai (South-East University (China)) , R. Feidenhans (Copenhagen University) , S. Holmes (Toshiba Research Europe) , G. Van Der Laan (Diamond Light Source)
Co-authored by industrial partner: Yes

Type: Journal Paper
Journal: Ieee Transactions On Magnetics , VOL 44 (11) , PAGES 2959-2965

State: Published (Approved)
Published: November 2008

Abstract: Hybrid spintronic structures, integrating half-metallic magnetic oxides and Heusler alloys with their predicted high spin polarization, are important for the development of second-generation spintronics with high-efficient spin injection. We have synthesized epitaxial magnetic oxide Fe 3O 4 on GaAs(100) and the unit cell of the Fe3O4 was found to be rotated by 45deg to match the gallium arsenide GaAs. The films were found to have a bulk-like moment down to 3-4 nm and a low coercivity indicating a high-quality magnetic interface. The magnetization hysteresis loops of the ultrathin films are controlled by uniaxial magnetic anisotropy. The dynamic response of the sample shows a heavily damped precessional response to the applied field pulses. In the Heusler alloy system of Co2MnGa on GaAs, we found that the magnetic moment was reduced for thicknesses down to 10 nm, which may account for the lower than expected spin-injection efficiency from the spin-light-emitting diode structures. Using the element-specific technique of X-ray magnetic circular dichroism (XMCD), the reduced spin moments were found to originate from the Mn rather than the Co atoms, and the improvement of the interface is thus needed to increase the spin injection efficiency in this system. Further studies of the I-V characteristics of Fe3O4/GaAs(100) and Fe3O4/MgO/GaAs(100) show that the Fe3 O4 -based spintronic structures have a well-defined Schottky or tunneling barrier of moderate barrier height, which is encouraging for high-efficient spin injection.

Diamond Keywords: Spintronics; Alloys

Subject Areas: Physics

Facility: 1.1 at SRS

Added On: 19/08/2009 23:07

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Quantum Materials Physics Electronics Magnetism Materials Science Metallurgy

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