Reduction of Low-Frequency Noise in Tunneling-Magnetoresistance Sensors With a Modulated Magnetic Shielding

Author

Van-Su Luong ; Chin-Hsiung Chang ; Jen-Tzong Jeng ; Chih-Cheng Lu ; Jen-Hwa Hsu ; Ching-Ray Chang

Author_Institution

Dept. of Mech. Eng., Nat. Kaohsiung Univ. of Appl. Sci., Kaohsiung, Taiwan

Volume

50

Issue

11

fYear

2014

fDate

Nov. 2014

Firstpage

1

Lastpage

4

Abstract

The high-noise level at low frequency in magnetic tunnel junction (MTJ) sensors is the key problem for their applications in measuring the low values of static magnetic field. In this paper, we investigated a shielding-type flux chopper to resolve the 1/f noise issue. By the using a cylindrical chopper with its axis perpendicular to the sensing direction of MTJ sensor, the noise at 1 Hz was reduced from 4 to 0.3 nT/√Hz by chopping the magnetic flux at 5 kHz. The reduction in noise can be qualitatively explained by the 1/f behavior and the chopping efficiency. The proposed method is promising in enhancing the detectivity of MTJ sensor for sensing the static geomagnetic field.

Keywords

1/f noise; magnetic field measurement; magnetic flux; magnetic noise; magnetic sensors; magnetic shielding; magnetoresistive devices; tunnelling magnetoresistance; 1/f noise; MTJ sensor; frequency 1 Hz; frequency 5 kHz; low-frequency noise reduction; magnetic tunnel junction sensor; modulated magnetic shielding; shielding-type flux cylindrical chopper; static geomagnetic field sensor; static magnetic field measurement; tunneling-magnetoresistance sensor; Choppers (circuits); Magnetic sensors; Magnetic shielding; Magnetic tunneling; Noise; Sensitivity; Low-frequency noise; magnetic noise; magnetic sensors; magnetic shielding;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2014.2329058

Filename

6971395