Résumé:

The principle of NMR is based on the detection of the magnetization originating from the spin of atomic nuclei. The spin is polarized by a static magnetic field and excited by radiofrequency pulses (wavelength about one meter), that tilt the axis of the magnetization. When the magnetization returns to equilibrium, with a classical receiving antenna, we detect the electromagnetic field. This contribution, we propose the use of a micrometer-sized probe positioned in the vicinity of the object of interest, at a distance shorter than the wavelength of the radiated NMR signal. Our microprobe presents innovative characteristics: a capacitive coupling (electric field component) and reduced dimensions for an accurate positioning, which ensure the detection of NMR signal from the sample.