Title :
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
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;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2014.2329058
