Abstract
Orthogonal fluxgate in fundamental mode has become a competitive sensor for low noise measurement of low frequency magnetic fields. The noise of this sensor has been recently reduced to 2.8 pT Hz at 1 Hz; however, it appears that noise lower than 2.5 pT/ Hzat 1 Hz cannot be achieved because of the physical limitations due to the intrinsic noise generated in the core of the fluxgate. In order to decrease the noise below 2.5 pT/ Hzat 1 Hz, Barkhausen noise generated in the core must be reduced. For this purpose, we annealed the amorphous wire used as the core of the sensor in an infrared furnace while a dc current was flowing through the wire. The dc current generated a circumferential field large enough to saturate the wire in a circumferential direction, and by annealing the saturated wire, we increased the circumferential anisotropy. We illustrate the dependence of circumferential anisotropy on dc current in the wire as well as on temperature and time of annealing. We then demonstrate that larger circumferential anisotropy helps reduce the noise of the sensor suppressing the Barkhausen noise when the fluxgate is operated in fundamental mode. As a result, a 1.8 pT/ Hznoise at 1 Hz was achieved with annealed wire, which is far below the 2.5 pT/ Hzminimum noise achievable for sensors with as-cast wires.
| Original language | English |
|---|---|
| Article number | 6392355 |
| Pages (from-to) | 62-65 |
| Number of pages | 4 |
| Journal | IEEE Transactions on Magnetics |
| Volume | 49 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 4 2013 |
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All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering
Cite this
Orthogonal fluxgate with annealed wire core. / Butta, Mattia; Sasada, Ichiro.
In: IEEE Transactions on Magnetics, Vol. 49, No. 1, 6392355, 04.01.2013, p. 62-65.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Orthogonal fluxgate with annealed wire core
AU - Butta, Mattia
AU - Sasada, Ichiro
PY - 2013/1/4
Y1 - 2013/1/4
N2 - Orthogonal fluxgate in fundamental mode has become a competitive sensor for low noise measurement of low frequency magnetic fields. The noise of this sensor has been recently reduced to 2.8 pT Hz at 1 Hz; however, it appears that noise lower than 2.5 pT/ Hzat 1 Hz cannot be achieved because of the physical limitations due to the intrinsic noise generated in the core of the fluxgate. In order to decrease the noise below 2.5 pT/ Hzat 1 Hz, Barkhausen noise generated in the core must be reduced. For this purpose, we annealed the amorphous wire used as the core of the sensor in an infrared furnace while a dc current was flowing through the wire. The dc current generated a circumferential field large enough to saturate the wire in a circumferential direction, and by annealing the saturated wire, we increased the circumferential anisotropy. We illustrate the dependence of circumferential anisotropy on dc current in the wire as well as on temperature and time of annealing. We then demonstrate that larger circumferential anisotropy helps reduce the noise of the sensor suppressing the Barkhausen noise when the fluxgate is operated in fundamental mode. As a result, a 1.8 pT/ Hznoise at 1 Hz was achieved with annealed wire, which is far below the 2.5 pT/ Hzminimum noise achievable for sensors with as-cast wires.
AB - Orthogonal fluxgate in fundamental mode has become a competitive sensor for low noise measurement of low frequency magnetic fields. The noise of this sensor has been recently reduced to 2.8 pT Hz at 1 Hz; however, it appears that noise lower than 2.5 pT/ Hzat 1 Hz cannot be achieved because of the physical limitations due to the intrinsic noise generated in the core of the fluxgate. In order to decrease the noise below 2.5 pT/ Hzat 1 Hz, Barkhausen noise generated in the core must be reduced. For this purpose, we annealed the amorphous wire used as the core of the sensor in an infrared furnace while a dc current was flowing through the wire. The dc current generated a circumferential field large enough to saturate the wire in a circumferential direction, and by annealing the saturated wire, we increased the circumferential anisotropy. We illustrate the dependence of circumferential anisotropy on dc current in the wire as well as on temperature and time of annealing. We then demonstrate that larger circumferential anisotropy helps reduce the noise of the sensor suppressing the Barkhausen noise when the fluxgate is operated in fundamental mode. As a result, a 1.8 pT/ Hznoise at 1 Hz was achieved with annealed wire, which is far below the 2.5 pT/ Hzminimum noise achievable for sensors with as-cast wires.
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UR - http://www.scopus.com/inward/citedby.url?scp=84871841082&partnerID=8YFLogxK
U2 - 10.1109/TMAG.2012.2218094
DO - 10.1109/TMAG.2012.2218094
M3 - Article
AN - SCOPUS:84871841082
VL - 49
SP - 62
EP - 65
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
SN - 0018-9464
IS - 1
M1 - 6392355
ER -