
Magnetic Sensors 239
Overhauser magnetometers utilize two resonances—
ESR and NMR. The ESR is used for polarization of NMR
sensor instead of being conventionally used in NMR sen-
sor large magnetic eld. An advantage of such solution
is small power and excitation in high-frequency range
not disturbing NMR operation (this way, practically,
continuous NMR operation is possible—5 samples/s in
GSM-19 instrument). Moreover, the polarization by ESR
resonance is much stronger than conventional polariza-
tion, which leads to high sensitivity and resolution.
To obtain both types of resonances, the sensor should
contain the material with free elect ...