| 摘要 |
PROBLEM TO BE SOLVED: To provide a method that can measure a weak magnetic field using a magnetoresistive sensor in a secondary harmonic detection mode.SOLUTION: There is provided a method including applying an AC drive current 430 to a drive strap 70 covering a magnetoresistive sensor 10 so as to move an operation position of the magnetoresistive sensor to a low-noise area, and further including generating an AC magnetic drive magnetic field 440 by the magnetoresistive sensor with the AC drive current, and extracting a secondary harmonic component of the output of the magnetoresistive sensor when a measured magnetic field 450 is superposed on the AC magnetic drive magnetic field of the magnetoresistive sensor. The measured magnetic field is in proportion to a signed amplitude of the extracted secondary harmonic component. |
