Research News
Scanning tunneling microscope image (50x50nm2) of organic molecules. The colouring reveals the different spin alignments. Photo: CFN
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Smallest Magnetic Field Sensor of the World
The use of organic molecules as building elements for electronics currently is being intensively researched. One problem in miniaturising is that the information is encoded by way of the electron's electric charge (power on or off), which is energy intensive. Alternatively, in spin electronics the information is encoded in the electron's own rotation, the spin. The advantage here is that the spin is maintained even when the power is switched off, thus enabling the building element to store information without using energy. A team of scientists from the KIT and the Institut de Physique et Chimie des Matériaux de Strasbourg now for the first time have managed to unite the concepts of spin electronics and molecular electronics in one construction element consisting of a single molecule. The organic molecule H2-Phthalocyanine, which is also used as blue dye in ballpoint pens, features a strong resistance dependency when clamped between spin polarised, that is, magnetic electrodes. This effect, first observed in purely metal contacts by Albert Fert and Peter Grünberg, is called giant magnetoresistance effect and was rewarded with the Nobel Prize for Physics in 2007. Construction elements based on this principle allow the production of particularly small and powerful magnetic field sensors for reading heads on hard drives or for non-volatile memories in order to further increase reading speed and data density.
