  Using standard nuclear magnetic resonance (NMR) technique and a
well-fabricated sample, we have succeeded in directly observing local magnetic
field generated by a micro-magnet Ni45Fe55 (the thickness of 400-nm) which was
sputtered on an Al layer of 20-nm thickness. Improved sensitivity of our NMR
technique enabled us to clearly observe Al-NMR signals, which are confirmed to
come from Al nuclei in the 20-nm layers. From the analysis of the Al-NMR
spectra, the local magnetic field was found to be +0.17+-0.02 (-0.20+-0.01)
Tesla, the sign of which is consistent with the geometry that the external
magnetic field was applied perpendicular (parallel) to the Al layer. The
present study gives a potential key element toward realizing higher resolution
in magnetic resonance imaging (MRI).
