During this project, ultrasensitive cantilevers designed for nuclear magnetic resonance applications were fabricated and characterised. The cantilevers are 500, 340 or 200 μm long, 10 or 20 μm wide and 500 or 340 nm thick and integrate a thin film of cobalt at the free end. This thin-film can be magnetised. Their fabrication requires novel techniques such as silicon-on-insulator technology, Al protective layer deposition, high anisotropic dry etching or HF-vapour release. A dynamic and a static model of the cantilevers were elaborated. The models describe the behaviour of the cantilevers when actuated by an external magnetic field in the air and in vacuum.