Low Temperature Magnetic Resonance Force Microscope: Design and Performance

We describe the design and operation of a cryogenic magnetic resonance force microscope suitable for detecting electron spin and ferromagnetic resonance. Microscope-critical components are described, including scanning probe stages, cantilever with a micromagnet attached, fiber optic interferometer, and microwave resonator. The performance of the apparatus has been evaluated at 4 K using diphenylpicrylhydrazyl (DPPH) as a reference sample. Our experiments have demonstrated the sensitivity of the microscope to be better than 3X104 electron spins.