Paramagnetic and ferromagnetic resonance imaging with a tip-on-cantilever magnetic resonance force microscope

Abstract

A magnetic resonance force microscope with a "tip-on-cantilever" configuration was used to compare imaging characteristics of paramagnetic and ferromagnetic samples. Three-dimensional electron paramagnetic resonance (EPR) imaging of diphenylpicrylhydrazil (DPPH) particles was accomplished by scanning the sample in two dimensions while stepping an external field. The EPR force map showed broad response reflecting the size and shape of the sample, allowing a three-dimensional real-space magnetization image to be successfully reconstructed. In contrast to the EPR case, ferromagnetic resonance imaging of a micron-scale yttrium iron garnet sample showed no significant line broadening despite the strong field gradient (∼10G/μm). Two-dimensional force maps revealed spatial dependence of magnetostatic and magnetoelastic modes. © 1998 American Institute of Physics.