Low-field NMR with magnetoresistive mixed sensors

Abstract

Event Abstract Back to Event Low-field NMR with magnetoresistive mixed sensors Natalia Sergeeva-Chollet1*, Hadrien Dyvorne1, Hedwige Polovy1, Myriam Pannetier-Lecoeur1 and Claude Fermon1 1 CEA, France Magnetoresistive sensors sensitivity has grown rapidly since the discovery of the Giant magnetoresistance effect (GMR). These sensors being field sensors, their sensitivity is independent of the size. For that reason, they have rapidly replaced coils in read heads. When coupled to a Giant Magnetoresistive (GMR) sensor, a superconducting loop containing a constriction can be an ultra sensitive magnetometer [1]. It has thermal noise levels of few fT/sqrt(Hz), comparable to LT- SQUID noise. These mixed sensors could be used for the detection of the biomagnetic signals like neuronal signature [2]. Furthermore, these devices are good candidates for low field Nuclear Magnetic Resonance (NMR) detection and Magnetic Resonance Imaging (MRI) especially at low and ultra low fields. They are very robust and accept strong RF pulses with a very short recovery time compared to tuned RF coils, which allow measurements of broad signals. We will show the results on NMR signal detection and first-MRI at low field without pre-polarization with such sensors. Finally, the perspectives of low-field MRI based on mixed sensors combined with neural signal detection (MEG) will be presented.