A magnetic field probe comprises a sample (4) that exhibits magnetic resonance at an operating frequency, an electrically conductive structure (8) surrounding the sample for receiving a magnetic resonance signal therefrom, and a solid jacket (12) encasing the sample and the conductive structure. The jacket is made of a hardened two-component epoxy system containing a paramagnetic dopant dissolved therein, with the concentration of the dopant being chosen such that the jacket has a magnetic susceptibility that is substantially identical to the magnetic susceptibility of the conductive structure.