Magnetoresistive magnetometer with improved bandwidth and response characteristics

Abstract

We report on the realization and characterization of a high performance, compact magnetometer based on a magnetoresistive sensor and working in the range ±600 T. The output is provided both numerically and by means of a field-proportional voltage. Spurious offset effects are suppressed by flipping the film magnetization at a frequency of 100 kHz, 2 / 3 orders of magnitude higher than in conventional applications. The design allows for a field resolution of 20 nT, low output noise density, and high precision and accuracy ͑relative full-scale uncertainty of about 500 ppm͒.

Crossfield Sensitivity in AMR Sensors

“…We have shown that separate processing of the and voltages instead of simple averaging leads to more efficient correction of the crossfield error. This is easy in digital magnetometers such as [11]. However, if field compensation is possible, such processing is not necessary.…”

Model for coil-less fluxgate

“…The only serious candidates for these applications are AMR sensors and miniaturized fluxgate sensors. While the precision of AMR sensors is limited to 10 nT [1,2], effort is given to develop small-size fluxgate sensors. One path is miniaturization of the classical parallel fluxgate [3][4][5], but the success in this direction is only slow.…”

Advances in Magnetic Field Sensors

“…The principles of AMR sensors are described in [13], comparative measurements of the noise of various magnetoresistors are shown in [14]. The best AMR sensors have a noise of 200 pT/ [15]; however, it is difficult to achieve pT noise values with the whole AMR magnetometer; realistic resolution is 10 nT [16].…”