White Paper: Electronics & Computers

The Rise of TMR Sensors


The technology used in tunnel-magnetoresistance (TMR) elements for sensors have been around since the 1980s, but mass production of TMR sensors has ramped up significantly in the past five years. The demand for such sensors has been exponentially rising, largely due to an appetite for their use in consumer electronics, automotive electronics, electrical vehicles and other industrial equipment. They are a significant part of a mobile phones and self-driving automobile’s systems.

TMR sensors vastly differ from anisotropic magnetoresistance (AMR) and giant magnetoresistance (GMR) sensors in terms of accuracy, output, thermal management, and are therefore used in different applications. In order to improve TMR sensors, manufacturers have recently introduced a new type of magnetic sensors utilizing a TMR element, which is a highly-sensitive reproducing element of an hard disk drive (HDD) magnetic head, with several improvements. These improvements result in as much as 6x the output of GMR sensors and 20x the output of AMR sensors. TMR sensors can also be used in other applications as angle and rotary sensors.

These improvements have been used to further evolve sensor technology. The magnetic structure of a TMR element is very similar to a GMR element with a few significant differences. In a TMR element, the current flows perpendicular to the film surface, while in a GMR element, it flows horizontally to the film surface.

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