Earth Magnetism Free High Sensitive Magnetic Field Sensor

Abstract

In order to realize a general purpose magnetic field sensor having a detection sensitivity of the order of 10^-12 T/√Hz in the room temperature, a problem of removing the effect of earth magnetism from the sensor has to be solved, because its magnitude is 4.5×10⁴ times larger than that in the range to be detectable. For this purpose, a well-known approach of exciting the sensor in the opposite direction to the earth magnetism to cancel out the value has been adopted. This paper aims at realizing a magnetic field sensor free from the earth magnetism by introducing a method called “zero magnetic field”. In practice, we developed such a sensor and the tested results confirmed that the detection performance was maintained without losing the high sensitivity.