Microscale 3D imaging by magnetic resonance force microscopy using full-volume Fourier- and Hadamard-encoding.

Three-dimensional spatially resolved full-volume imaging by magnetic resonance force microscopy at room temperature is described. Spatial resolution in z-dimension is achieved by using the magnetic-field gradient of a ferromagnetic particle that is also used for the force detection of the magnetic resonance. The gradient of the radiofrequency pulses generated by two separate wire-bonded microcoils is used for spatial resolution in x- and y-dimension. To enhance the sensitivity of our measurement Hadamard- and Fourier-encoding schemes are applied due to their multiplex effect. Measurements were taken on a patterned (NH4)2SO4 crystal sample. From the calculated magnetic field distributions, a 3D image was reconstructed with a voxel volume of about 5 µm3 (1.2 µm × 3.0 µm × 1.4 µm in x-, y- and z-dimension).

Detection of liquids by magnetic resonance force microscopy in the gradient-on-cantilever geometry.

We demonstrate the detection of picoliter amounts of water and triethylenetetramine by a magnetic-resonance-force-microscopy (MRFM) setup operated in the gradient-on-cantilever geometry at room temperature. A magnetic field gradient is produced by a ferromagnetic SmCo particle glued to the tip of a micromechanical resonator (cantilever). The liquids are enclosed in a micro-capillary to protect them from the high vacuum environment needed for sensitive detection. We describe simple spectroscopic experiments as proton T1 - relaxation, Rabi nutation curves and Hahn-echo measurements.