Magnetic resonance detection and imaging using force microscope techniques (invited)

We describe the principles and imaging characteristics of a new type of high resolution magnetic resonance microscopy. Magnetic resonance is detected by measuring a small oscillating magnetic force acting between the spins in a sample and a nearby ferromagnetic particle. The oscillating magnetic force is generated by polarizing the spins in the magnetic field and then modulating the sample magnetization using magnetic resonance techniques. The oscillating magnetic force is detected by sensing the angstrom-scale vibration of a micromechanical cantilever on which the sample is mounted. High spatial resolution is achieved as a result of the narrowness of the magnetic resonance spectral response and the large magnetic field gradient generated by the ferromagnetic particle. Electron paramagnetic resonance images are presented that demonstrate axial resolution on the order of 1 μm and lateral resolution on the order of 5 μm. Submicron resolution can be expected with straightforward technical improvements.