Simultaneous Measurement of Two DC Magnetic Field Components by a Single Magnetoresistor

The method relies on a special excitation mode which causes uniform rotation of magnetization in the plane of a barber-pole magnetoresistive sensor. It is interesting that the uniform rotation of the magnetization is attained when the excitation field is not uniformly rotating. The rotation of this field should rather be elliptically polarized. The two orthogonal components of an external in-plane measured dc field disturb the uniform rotation of the magnetization in different instances of time. This behavior of the magnetization enables simultaneous but still separate measurements of both external field components by detection of the time shifts between the corresponding zero-crossing points of the sensor ac output and the zero-crossing points of the corresponding orthogonal components of the excitation field. The experimental results confirm the applicability of the method. Possible applications are reviewed.