First images from a magnetic resonance force microscope

We describe a new magnetic resonance imaging technique based on the measurement of magnetic force acting between a magnetic tip and the resonantly excited spins in the sample. Magnetic resonance force maps of the sample are formed by scanning the tip with respect to the sample while measuring the angstrom-scale vibration of a microcantilever holding the sample. Real-space spin density information can be recovered from the force maps by using a simple image reconstruction technique. The technique was demonstrated for electron spin resonance in micrometer-size particles of diphenylpicrylhydrazil. Using a tip that generates a field gradient of 4.3 G/μm, a lateral resolution of 5 μm, and an axial resolution of 1 μm was achieved.