Spin–orbit magnetic state readout in scaled ferromagnetic/heavy metal nanostructures

The efficient detection of a magnetic state at nanoscale dimensions is important for the development of spin-logic devices. Magnetoresistance effects can be used to detect magnetic states, but they do not generate an electromotive force (that is, a voltage) or a current that can be used to drive a circuit element for logic device applications. Here we report a favourable scaling law for the detection of an in-plane magnetic state of a magnet by using the inverse spin Hall effect in cobalt–iron/platinum (CoFe/Pt) nanostructured devices. By reducing the dimensions of the device, we obtain a large spin Hall signal of 0.3 Ω at room temperature and quantify an effective spin-to-charge conversion rate for the ferromagnetic/heavy metal system. We predict that this spin–orbit detection of magnetic states could be used to drive spin-logic circuits.