Wspólnotowy Serwis Informacyjny Badan i Rozwoju - CORDIS

First spin injection via tunnel barrier

A GaAs based LED has been combined with a tunnel barrier and a CoFe ferromagnetic contact. Under bias spin polarized electrons can be injected from the contact into the LED. The spin polarisation persists even at elevated temperatures.

Different types of tunnel barriers have been used:
(1) amorphous oxide tunnel barriers such as AlOx are very robust and can be deposited by simple techniques such as sputtering and in-situ oxidation. They give good spin injection results, up to 30% at low temperature and close to 20% at room temperature.
(2) Highly doped Schottky barriers give more symmetric behaviour and are well suited for both injection AND detection. The obtained spin polarization and temperature dependence are similar to the AlOx tunnel barriers. Schottky injectors require more sophisticated growth techniques such as molecular beam epitaxy, but they also allow the growth of epitaxial ferromagnetic contacts with better control over the magnetic properties such as the anisotropy.

Reported by

IMEC
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