Magnetocardiography with sensors based on giant magnetoresistance

International audienceBiomagnetic signals, mostly due to the electrical activity in the body, are very weak and they canonly be detected by the most sensitive magnetometers, such as Superconducting QuantumInterference Devices SQUIDs. We report here biomagnetic recordings with hybrid sensors basedon Giant MagnetoResistance GMR.We recorded magnetic signatures of the electric activity of thehuman heart magnetocardiography in healthy volunteers. The P-wave and QRS complex, knownfrom the corresponding electric recordings, are clearly visible in the recordings after an averagingtime of about 1 min. Multiple recordings at different locations over the chest yielded a dipolarmagnetic field map and allowed localizing the underlying current sources. The sensitivity of theGMR-based sensors is now approaching that of SQUIDs and paves way for spin electronics devicesfor functional imaging of the body