Three-dimensional sensing of the magnetic-field vector by a compact planar-type Hall device

Smart society is forthcoming with a rapid development in the automation of electric appliances requiring abundant sensors. One of the key sensors is a three-dimensional magnetometer for detecting the motion of objects, which is usually driven by cooperative multiple sensors on three orthogonal planes. Here, we demonstrate the fundamental operation of a three-dimensional magnetometer based on a simple Fe-Sn heterostructure Hall device in a planar geometry. Polar coordinates of the magnetic-field vector are uniquely determined by the combination of the sizable anomalous Hall effect, the anisotropic magnetoresistance, and the unidirectional magnetoresistance. Thanks to the ferromagnetic topological features in the Fe-Sn heterostructure, the above-mentioned device overcomes the limitation of conventional semiconductor devices and is highly sensitive even at room temperature. The compact planar geometry will be particularly useful in versatile electrical applications requiring a low-cost three-dimensional magnetometer with space- and energy-saving features. Three-dimensional magnetometers are key for detecting the motion of objects in automated electronics, but typically require multiple sensors on orthogonal planes. Here, a compact planar-type 3D magnetometer with low power consumption is realized using a topological ferromagnetic Fe-Sn heterostructure.