Saturation of spin-polarized current in nanometer scale aluminum grains

[摘要] We describe measurements of spin-polarized tunneling via discrete energy levels of single aluminum grains. In high resistance samples (similar to G Omega), the spin-polarized tunneling current rapidly saturates as a function of the bias voltage. This indicates that the spin-polarized current is carried only via the ground state and the few lowest in energy excited states of this grain. At the saturation voltage, the spin-relaxation rate T-1(-1) of the highest states excited by tunneling is comparable to the electron tunneling rate, T-1(-1)approximate to 1.5x10(6) and 10(7) s(-1), in two samples. The ratio of T-1(-1) to the electron-phonon relaxation rate is in agreement with the Elliot-Yafet scaling, an evidence that spin relaxation in Al grains is governed by the spin-orbit interaction.

[发布日期] 2007-11-01

[关键词] SPECTROSCOPY;TRANSPORT