Crocus Technology has developed and patented its advanced XtremeSense TMR technology (Tunnel Magneto-Resistance) to provide superior magnetic sensing performance for use in many applications. The advanced XtremeSense TMR technology enables high magnetic sensitivity, stable performance over temperature, low noise and low power consumption which allows it to be used in a broad spectrum of applications. TMR sensors can replace many Hall Effect sensors with increased performance and cost savings.
TMR is based on different physics phenomena. The magneto-resistance effect is the property of a device to change its electrical resistance value under the influence of an external magnetic field, therefore allowing enhanced electrical detection of magnetic fields in various applications.
At the heart of the advanced XtremeSense TMR technology, is a thin-film magnetoresistive device, the so-called Magnetic Tunnel Junction (MTJ). In its simplest form the MTJ consists of two electric-conducting magnetic layers on either side of a thin (nanometer-scale) but highly robust insulating layer. One magnetic layer has a fixed magnetic moment direction, while the other can change freely to follow the direction of the local magnetic field.
According to classic physics, despite how thin the insulating layer is, it should prevent any current flow between the two magnetic layers. However, in this nano-world, quantum physics allows electrons to “tunnel” across the atoms of the thin insulating material with a resistance that depends on the sensitivity of the relative orientation of the two magnetic layers. Therefore, as the Free Layer magnetization follows the direction and intensity of the ambient magnetic field, its magnetic orientation is modified with respect to the Reference Layer. This change in relative magnetic orientation will significantly change the probability of quantum tunneling between the two layers and therefore the electron flow through the device.
TMR sensors more accurately measure the full dynamic range and provides a cleaner signal.