Spin-filtering of non-equilibrium holes in semiconductor-ferromagnet hybrid structure

E. Ul Haq, T. Banerjee, Martin Herman Siekman, J.C. Lodder, R. Jansen

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    Although spin-dependent transmission of hot electrons has been well addressed, the complementary spin-transport of non-equilibrium holes (below the Fermi level) has never been studied. Using a semiconductor/ferromagnet hybrid structure, it is shown here that a thin ferromagnetic film acts as an efficient spin-filter for holes. This has important implications not only in understanding several non-equilibrium phenomena, but also in realizing complementary building blocks for use in spintronics. To investigate hole spin transport, Ballistic Hole Magnetic Microscopy (BHMM) has been developed. Here, the tip of an STM is positively biased such that unpolarized hot holes are injected into a ferromagnetic metal stack grown on top of a p-type Si semiconductor. A Schottky contact between Au and p-Si acts as the collector energy barrier for the transmitted holes. Hot hole transport with energies of 0.3 to 2 eV below the Fermi level has been studied for a p-Si/Au/Co stack with varying Co thickness. The hole attenuation length has been found to be short and increases from 6-10 /spl Aring/ in the energy range 0.8-2 eV. For a NiFe/Au/Co trilayer, the hole transmission is clearly spin dependent with a large magnetocurrent (MC) of 130%.
    Original languageUndefined
    Title of host publicationIEEE International Magnetics Conference - INTERMAG Asia
    Place of PublicationUSA
    Number of pages1
    ISBN (Print)0-7803-9009-1
    Publication statusPublished - 2005
    Event2005 IEEE International Magnetics Conference, INTERMAG ASIA 2005 - Nagoya, Japan, Nagoya, Japan
    Duration: 4 Apr 20058 Apr 2005

    Publication series

    NamePhysics of Spin Injection
    PublisherIEEE Magnetics Society
    VolumeSessions FA


    Conference2005 IEEE International Magnetics Conference, INTERMAG ASIA 2005
    Abbreviated titleINTERMAG ASIA 2005
    Other4-8 April 2005


    • METIS-226844
    • EWI-19123
    • IR-53688

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