Researchers from the Physical and Technical Institute in Braunschweig, Germany have discovered that waste heat can be used inside magnetic tunnel structures (such as those used in MRAM chips). This means that such structures may be used to monitor and control "thermoelectric voltages" and currents in highly integrated electronic circuits.

In their experiments, the scientists generated a temperature difference between the two magnetic layers and investigated the electric voltage (or "thermoelectric voltage") generated hereby. It turned out that the thermoelectric voltage depends on the magnetic orientation of the two layers nearly as strongly as the electric resistance. By switching the magnetization, it is therefore possible to control the thermoelectric voltage and, ultimately, also the thermal current flowing through the specimen.

In the future, this new effect could be applied, for example, by using and converting the energy of waste heat occurring in integrated circuits in a targeted way.