Sensitivity and spatial resolution for electron-spin-resonance detection by magnetic resonance force microscopy

The signal intensity of electron spin resonance in magnetic resonance force microscopy (MRFM) experiments employing periodic saturation of the electron spin magnetization is determined by four parameters: the rf held H-1, the modulation level of the bias field H-m, the spin relaxation time tau(1), and the magnetic size R(partial derivative H/partial derivative z) of the sample. Calculations of the MRFM spectra obtained from a 2,2-diphenyl-1-picrylhydrazyl particle have been performed for various conditions. The results are compared with experimental data and excellent agreement is found. The systematic variation of the signal intensity as a function of H-1 and H-m provides a powerful tool to characterize the MRFM apparatus. (C) 1996 American Institute of Physics.