Spintronics Takes an Unusual Turn to Harvest Energy at Room Temperature

Spintronics, when combined with thermodynamics, creates an electric generator that utilizes the electron spin to harvest energy at room temperature. (Image credit: Martin Bowen)

Scientists from the CRNS, the University of Strasbourg, the University of Lorraine, and Uppsala University have discovered a way to harvest thermal energy at room temperature by combining spintronics and quantum thermodynamics. Spintronics utilizes the spin of an electron and its associated magnetic moment in solid-state devices, meaning it’s an excellent tool for data storage technologies. On the other side of the coin, quantum thermodynamics is the merging of two theories with one dealing with heat and temperature and the other dealing with the nature of subatomic particles.

The scientists were able to merge both theories to create an electrical engine, or more appropriately, a spin engine with the basic idea of using the electron spin to harvest thermal fluctuations at room temperature. Garnering those fluctuations occurs over pragmatic centers or atomic-level magnets whose orientation oscillates because of heat. Spintronic selectors act as the engine’s electrodes, allowing electrons of only one spin to conduct (up for red, down for blue in the above diagram).

As heat mixes the electron spin on the pragmatic center with energetically separated spin energy levels, transport between the practical centers happens at different energy levels for each electrode. This generates a bias voltage to appear between the electrodes, allowing a current to flow when the circuit is closed. The scientists utilized analytical and ab-initio theories to test their breakthrough and found a link between their spin engine and room temperature experiments used on a spintronic device known as a magnetic tunnel junction (MTJ- a magnesium oxide tunneling barrier sandwiched between a set of two ferromagnetic electrodes).

The scientists state that if they could mass-produce those spin engines at high success quantities, it could lead to new data storage, communications, and renewable energy devices with incredible energy efficiencies.  

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