| 摘要 |
A highly-sensitive, physically small and rugged magnetometer employs a magnetostrictive amorphous metal ribbon core. A piezoelectric driver induces stress variations in the ribbon of a magnitude determined by an external magnetic field. The amplitude of the variations in magnetization is sensed by a pick-up winding disposed around the ribbon core. The dynamic range of the device is improved by employing a nulling field winding around the core to continuously null out the magnetization of the core. In contrast to the non-linear characteristic of the conventional fluxgate magnetometer, the invention provides a linear response to magnetic field strength which simplifies the processing circuitry. In addition, the ribbon may be field-annealed to improve the sensitivity of the device. Still further, low-frequency stresses in the ribbon (due to thermal expansion and the like) are relieved with a viscous fluid interface between the ribbon and support to thereby reduce low-frequency noise in the output signal and drifts in the calibration.
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