Anisotropic magneto-resistive (AMR) sensor

The Honeywell HMC1002 / HMC1051Z magnetometer are magnetoresistive sensors. The anisotropic magnetoresistive (AMR) sensor is one type that lends itself well to the Earth's field sensing range. They can sense dc static fields as well as the strength and direction of the field.

Basically, it is made of a nickel-iron (Permalloy) thin film deposited on a silicon wafer and is patterned as a resistive strip. The properties of the AMR thin film cause it to change resistance by 2 - 3 % in presence of a magnetic field.

Typically, four of these resistors are connected in a Wheatstone bridge configuration so that both magnitude and direction of a field along a single axis can be measured. The key benefit of AMR sensors is that they can be bulk manufactured on silicon wafers and mounted in commercial integrated circuit packages.

Please refer to "Applications using AMR Magnetic Sensors" for more details of the AMR sensors.