Determining Exchange Splitting in a Magnetic Semiconductor by Spin-Filter Tunneling
CALIFORNIA UNIV BERKELEY LAWRENCE BERKELEY LAB
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A large exchange splitting of the conduction band in ultrathin films of the ferromagnetic semiconductor EuO was determined quantitatively, by using EuO as a tunnel barrier and fitting the current-voltage characteristics and temperature dependence to tunneling theory. This exchange splitting leads to different tunnel barrier heights for spin-up and spin-down electrons, and is large enough to produce a near fully spin-polarized current. Moreover, the magnetic properties of these ultrathin films 6 nm show a reduction in Curie temperature with decreasing thickness, in agreement with theoretical calculation.
- Electrical and Electronic Equipment
- Properties of Metals and Alloys
- Solid State Physics