  Magnetic skyrmions are topologically protected local magnetic solitons that
are promising for storage, logic or general computing applications. In this
work, we demonstrate that we can use a skyrmion device based on [W/CoFeB/MgO] 1
0 multilayers for three-dimensional magnetic field sensing enabled by
spin-orbit torques (SOT). We stabilize isolated chiral skyrmions and stripe
domains in the multilayers, as shown by magnetic force microscopy images and
micromagnetic simulations. We perform magnetic transport measurements to show
that we can sense both in-plane and out-of-plane magnetic fields by means of a
differential measurement scheme in which the symmetry of the SOT leads to
cancelation of the DC offset. With the magnetic parameters obtained by
vibrating sample magnetometry and ferromagnetic resonance measurements, we
perform finite-temperature micromagnetic simulations, where we investigate the
fundamental origin of the sensing signal. We identify the topological
transformation between skyrmions, stripes and type-II bubbles that leads to a
change in the resistance that is read-out by the anomalous Hall effect. Our
study presents a novel application for skyrmions, where a differential
measurement sensing concept is applied to quantify external magnetic fields
paving the way towards more energy efficient applications in skyrmionics based
spintronics.
