[10p-Z08-11~17] 10.3 Spin devices, magnetic memories and storages

[10p-Z08-16] Development of highly sensitive and low noise TMR magnetic sensor for bio-magnetic field measurement

〇Kousuke Fujiwara¹, Mikihiko Oogane², Sabri Cakir¹, Seiji Kumagai¹, Tadashi Arimoto³, Yasuo Ando^1,2 (1.Spin Sensing Factory Corp., 2.Tohoku Univ., 3.KONICA MINOLTA, INC.)

Keywords:magnetic sensor, bio magnetic field, magnetocardiography

We have developed TMR sensor with magnetic resolution of 7 pT/√Hz @ 1 Hz. In the magnetocardiography measurement, an R peak due to the heartbeat was observed, and a clear QRS peaks was observed by averaging. We also succeeded in reducing the magnetic noise to about half by using the free layer that was magneto-statically coupled. Furthermore, we succeeded in dramatically reducing environmental noise by preparing a gradiometer with a sensor close to the signal source and a sensor far from the signal, and demonstrated the feasibility of a highly sensitive magnetic sensor that does not require a magnetic shielded room.