The team utilized analytical and ab-initio theories to establish a link between this spin engine concept and room-temperature experiments on a solid-state spintronic device called a magnetic tunnel junction (MTJ). Here, the interface between the ferromagnetic metal Co and carbon atoms was used as a spintronic selector, and carbon atoms substituting oxygen atoms in the MgO tunnel barrier as PM centers.
According to the experiments, if such devices could be mass produced at high success yields, then at present densities of MgO MTJs within next-generation memories, this concept could yield chips that continuously produce electrical power with an areal power density that is 3x greater than raw solar irradiation on Earth. The challenge is now to confirm certain fundamental aspects of this engine’s operation, to achieve device reproducibility by controlling at the atomic level the position and properties of the PM centers in a suitable solid-state device, to implement CMOS back-end integration (e.g. thanks to existing progress with MgO MTJ technologies), to manage engineering issues such as heat flow and interconnect losses, and to drastically lower the resulting chip’s areal cost.
To avert climate catastrophe within the GIEC-determined 11-year timeframe using a technological solution such as this one will require a massive, focused undertaking akin to that deployed in the Manhattan project, combining scientists, decision-/policy-makers and industrial partners already working on MTJ-based spintronic technologies. The website ‘www.spinengine.tech’ under construction will help to communicate on this undertaking. As a measure of hope, only 7-9 years elapsed between the discovery (in 1986-1988) of spintronics and first commercial products (1995). If the solution to the climate crisis is to involve new technology, then the maturation of this, and hopefully other, radically new physical concepts that can be technologically fast-tracked should from now on be considered with the urgency and prioritization that the stakes of a climate catastrophe portend.
This scientific work was published in Communications Physics on Sept. 25th 2019, thanks to experiments conducted on March 14th 2017, with financial support from the Institut Carnot MICA (project ‘Spinterface’), from the ANR (ANR-09-JCJC-0137, ANR-14-CE26-0009-01), the Labex NIE “Symmix” (ANR-11-LABX-0058 NIE) and Vetenskapsrådet. This work was performed using HPC resources from the Strasbourg Mesocenter and from the GENCICINES Grant 2016-gem1100. DOI: 10.1038/s42005-019-0207-8