Magnetoresistive detection of spin waves

We explore a detection method for spin waves consisting in integrating a magnetoresistive sensor on a magnonic waveguide. When subjected to the stray magnetic field generated by the spin wave, the relative orientation of the magnetizations of the two magnetic layers in the sensor oscillates in time, resulting in an electrical resistance change according to the so-called giant magnetoresistance effect. Upon application of an appropriate current bias, this variation of resistance translates into a sizable microwave voltage. At the submicrometer scale explored here, this signal is about 50 times larger than the one extracted from conventional inductive measurements of spin waves for comparable detection areas. Moreover, this detection scheme is expected to scale very favorably down to the nanometer size relevant for future magnon-based data processing architectures.