Interface electrical properties of Fe3O4/MgO/GaAs(100) epitaxial spin contacts

✍ Scribed by Wong, Ping Kwan Johnny ;Zhang, Wen ;Xu, Yongbing

• Book ID: 105366374
• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 230 KB
• Volume: 208
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.201084175

✦ Synopsis

Abstract

We have successfully accomplished the growth and fabrication of two types of molecular‐beam epitaxy‐grown Fe~3~O~4~‐based spin contacts on GaAs(100): (i) Fe~3~O~4~/GaAs direct contact, and (ii) Fe~3~O~4~/MgO/GaAs tunnel junction, both of which can be potentially used for electrical spin injection and detection at room temperature. Using current–voltage (I–V) measurements, we show, for the first time, the very different interface electrical properties of those epitaxial spin contacts on GaAs(100) surfaces. A more symmetric I–V relationship has been revealed in Fe~3~O~4~/MgO/GaAs(100) tunnel junctions, meaning that thermionic emission, which is important in epitaxial Fe~3~O~4~/GaAs(100) no longer plays a dominant role and that electron tunneling across the MgO tunnel barrier takes over the electronic transport characteristics. Moreover, by manipulating the MgO layer thickness (0.5 to 3.0 nm), the contact resistance of the tunnel junctions, a prerequisite parameter determining the efficiency of spin injection and detection into GaAs, can be tuned over three orders of magnitude.