  Spin-polarized field-effect transistor (spin-FET), where a dielectric layer
is generally employed for the electrical gating as the traditional FET, stands
out as a seminal spintronic device under the miniaturization trend of
electronics. It would be fundamentally transformative if optical gating was
used for spin-FET. We report a new type of spin-polarized field-effect
transistor (spin-FET) with optical gating, which is fabricated by partial
exposure of the (La,Sr)MnO3 channel to light-emitting diode (LED) light. The
manipulation of the channel conductivity is ascribed to the enhanced scattering
of the spin-polarized current by photon-excited antiparallel aligned spins. And
the photon-gated spin-FET shows strong light power dependence and reproducible
enhancement of resistance under light illumination, indicting well-defined
conductivity cycling features. Our finding would enrich the concept of spin-FET
and promote the use of optical means in spintronics for low power consumption
and ultrafast data processing.
