Applied Physics

Spin Injection Withstands the Heat

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Science  20 Jan 2006:
Vol. 311, Issue 5759, pp. 307
DOI: 10.1126/science.311.5759.307b

The efficient injection of polarized spins into semiconductors is the keystone capability for spintronics applications. Recent work has shown that epitaxially grown MgO on a ferromagnetic layer results in a dramatic enhancement of the spin-polarized injection efficiency, which has been demonstrated in several practical structures such as ferromagnet/oxide/ferromagnet spin filters and ferromagnet/oxide/semiconductor systems. However, polarized photoluminescence from a semiconductor quantum well, a technique routinely used to determine the extent of the spin polarization and spin injection efficiency, usually exhibits somewhat complex behavior in terms of temperature dependence.

Salis et al. report that the spin injection efficiency from CoFe/MgO electrodes is around 70% and is actually independent of temperature from 10 K all the way up to room temperature. The temperature dependence of the photoluminescence arises from the temperature dependence of the carrier recombination rate in the quantum well itself, a result that bodes well for the application of such spin-injecting electrodes in other spintronic devices. — ISO

Appl. Phys. Lett. 87, 262503 (2005).

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