Separation of electron spin filtering and magnetic circular dichroism effects in photoexcitation studies of hybrid ferromagnet∕GaAs Schottky barrier structures

Abstract

Spin dependent electron transport across $\text{ferromagnet}∕\mathrm{GaAs}$ Schottky barrier interfaces has been investigated at room temperature using photoexcitation techniques. We carried out a careful quantitative analysis that enabled us to precisely separate magneto-optical effects and spin filtering. Significant spin filtering effects were seen in $\mathrm{NiFe}∕\mathrm{GaAs}$ and $\mathrm{Fe}∕\mathrm{GaAs}$ structures at forward bias, whereas at reverse bias only magnetic circular dichroism was found. The observed effect strongly depends on the details of the Schottky barrier, suggesting that electron tunneling is the relevant transport mechanism.