The disclosure concerns a magnetometer for detecting a magnetic field, comprising: a solid state electronic spin system containing a plurality of electronic spins and a solid carrier, wherein the electronic spins are configured to be capable of aligning with an external magnetic field in response to an alignment stimulus; and a detector configured to detect an alignment response of the electronic spins, such that the external magnetic field can be detected; wherein the electronic spins are provided as one or more groups, each group containing a plurality of spins, the plurality of spins in each of the one or more groups being arranged in a line that is angled at an angle Θ with respect to the local direction of the external magnetic field at the said group. Also disclosed is a method for detecting a magnetic field.