Abstract

In spin-orbit coupled magnetic materials the chemical potential depends on the orientation of the magnetisation. By making the gate of a field effect transistor magnetic, it is possible to tune the channel conductance not only electrically but also magnetically. Here, we demonstrate the spin-gating effect for an aluminium single electron transistor (SET) gated by GaMnAs. The conductance variation of the SET provides a direct probe of the magnetisation dependent change in the chemical potential of the magnetic gate with μeV resolution. In performing magnetic field sweeps in fixed directions we also observe the non-linearity of the chemical potential in GaMnAs. The control of a transistor conductance by the gate magnetisation demonstrates a new approach for constructing spin transistors: instead of spin-transport controlled by ordinary gates we spin-gate ordinary charge transport.