They detect changes, or disturbances in magnetic fields that have been created or modified by objects or events. The magnetic fields may therefore carry information on properties such as direction, presence, rotation, angle, or electrical currents that is converted into an electrical voltage by the magnetic sensor. Magnetoresistive sensors are very small components that are designed to sense an applied magnetic field. Because no electrical contact is required, the sensor can operate across a relatively large air gap. To make embedding possible, magnetoresistive sensors are designed to be small and operate on very little power.
Some applications for the MR sensor used as open/close position sensor can be mobile phone application in the consumer market, security systems in the industrial market, or big and small appliances for the detection of the door position or the lead position (fridge, oven, bread machine).
Other than semiconductor magnetoresistive element, (SMR), there are three kinds of sensors as representative examples of the magnetoresistive element using a ferromagnetic thin film material such as anisotropic magnetoresistive element, (AMR), giant magnetoresistive element, (GMR), and tunnel magnetoresistive element.
