This sensor is made form a magnetic resistance effect element (MR element). The change in the magnetic field and the existence of the magnetic substance can be known as a change in the voltage. Magnetoresistance．．．The phenomenon that solid electric resistance changes by the magnetic field.
A change in the output voltage and the distance of the MR sensor and the thing detected
It is different from the magnetic head, a MR sensor can get 50% of the signals even if a distance with the detection object leaves 0.3mm.
The temperature characteristic of the MR sensor resistance value
A MR sensor is using InSb of the compound semiconductor. Because of that, that resistance value changes by temperature, and a rate of change is about -2%/C.
The temperature characteristic of the MR sensor output voltage
Temperature coeficient is about -0.6 %/deg. (at room temperature)