Low frequency excess noise source investigation of off-diagonal GMI-based magnetometers

Basile Dufay (1) , Elodie Portalier (1) , Sébastien Saez (1) , Christophe Dolabdjian (1) , Arthur Yelon (2) , David Ménard (2)

1 Equipe Electronique - Laboratoire GREYC - UMR6072
2 Département de génie physique [Montréal]

The impact of low frequency magnetization fluctuations on the equivalent magnetic noise of GMI sensors has recently been investigated [1]. It appears that this noise source may explain the low frequency excess noise exhibited by such sensors [2], in the 1/f regime. As a consequence, we propose to extend the noise model of off-diagonal GMI-based magnetometers presented in [2], to this regime. The model, based on classical GMI equations, includes magnetization fluctuation noise sources. The equivalent magnetic noise level is then computed from the sensitivity of each term of the sensing element impedance matrix to the magnetization angle at the static working point (for both axial and circumferential static magnetic field) and to conditioning circuitry. We have obtained new criteria for optimizing the conditioning of the sensor signals. We highlight key parameters of the intrinsic properties of the sensing element responsible for the ultimate equivalent magnetic noise performance. Preliminary results lead to an expected equivalent magnetic noise (cf. figure 1), at 1 Hz, in the range of 10 pT/√Hz, for physical GMI properties and conditioning parameters similar to those employed in [2]. ----------------------------------------- References: [1] C. Dolabdjian, B. Dufay, S. Saez, A. Yelon and D. Menard, Is low frequency excess noise of GMI induced by magnetization fluctuations?, International Conference on Materials and Applications for Sensors and Transducers, ICMAST, 2013. [2] B. Dufay, S. Saez, C. Dolabdjian, A. Yelon and D. Menard, Characterization of an optimized off-diagonal GMI-based magnetometer, IEEE Sensors Journal, vol. 13, no. 1 (2013), pp. 379—388.

Domaines: Electronique

Basile Dufay, Elodie Portalier, Sébastien Saez, Christophe Dolabdjian, Arthur Yelon, et al.. Low frequency excess noise source investigation of off-diagonal GMI-based magnetometers. European Magnetic Sensors and Actuators Conference 2014, Jul 2014, Vienne, Austria. ⟨hal-01109729⟩