  We demonstrate a three-terminal spin wave-based device utilizing spin wave
interference. The device consists of three coplanar transmission lines
inductively coupled to the 100nm thick CoFe film. Two spin wave signals are
excited by microwave fields produced by electric current in two sets of lines,
and the output signal is detected by the third set. The initial phases of the
spin wave signals are controlled by the direction of the current flow in the
excitation set of lines. Experimental data show prominent output signal
modulation as a function of the relative phase (in-phase and out-of phase) of
two input signals. The micrometer scale device operates in the GHz frequency
range and at room temperature. Our experimental results show that spin-wave
devices exploiting spin wave interference may be scaled to micrometer and
nanometer scales for potential logic circuit application.
