Spin-driven electrical power generation at room temperature

K Katcko,M Hehn,E Urbain,D Lacour,B Taudul,F Schleicher,J Fransson,D Spor,M Bowen,M Alouani,J Arabski,B Vileno,S Boukari,E Beaurepaire,W Weber

doi:10.1038/s42005-019-0207-8

Abstract

On-going research is exploring novel energy concepts ranging from classical to quantum thermodynamics. Ferromagnets carry substantial built-in energy due to ordered electron spins. Here, we propose to generate electrical power at room temperature by utilizing this magnetic energy to harvest thermal fluctuations on paramagnetic centers using spintronics. Our spin engine rectifies current fluctuations across the paramagnetic centers’ spin states by utilizing so-called ‘spinterfaces’ with high spin polarization. Analytical and ab-initio theories suggest that experimental data at room temperature from a single MgO magnetic tunnel junction (MTJ) be linked to this spin engine. Device downscaling, other spintronic solutions to select a transport spin channel, and dual oxide/organic materials tracks to introduce paramagnetic centers into the tunnel barrier, widen opportunities for routine device reproduction. At present MgO MTJ densities in next-generation memories, this spin engine could lead to ‘always-on’ areal power densities that are highly competitive relative to other energy harvesting strategies.

Highlights

On-going research is exploring novel energy concepts ranging from classical to quantum thermodynamics
Inspired by the report of Miao et al.[2], and by recent progress in quantum thermodynamics[3,4,5,6,7,8,9,10,11,12], we propose that a spin-split paramagnetic (PM) quantum object can enable electrons with a spin ↑ or ↓ quantum property to flow in opposite directions if the transmission rates on either side of the PM center are spindependent
To achieve a strongly spin-dependent transmission rate Γ, the PM center is placed between spintronic selectors—materials systems that ideally favor only one transport spin channel while blocking the other

Summary

Introduction

On-going research is exploring novel energy concepts ranging from classical to quantum thermodynamics. Two low-temperature experiments[1,2] have suggested that, by astutely designing the magnetic potential landscape of a quantum dot (QD) device, electrons with a spin ↑ or ↓ quantum property can flow in opposite directions This can generate electrical power if the spin ↑ and ↓ current channels are imbalanced, i.e. if the overall current is spin-polarized. Inspired by the report of Miao et al.[2], and by recent progress in quantum thermodynamics[3,4,5,6,7,8,9,10,11,12], we propose that a spin-split paramagnetic (PM) quantum object can enable electrons with a spin ↑ or ↓ quantum property to flow in opposite directions if the transmission rates on either side of the PM center are spindependent Differing amplitudes in these transport spin channels generate a spontaneous current flow. Our work confirms the high transport spin polarization at room temperature of the ferromagnetic metal/ molecule interface[13] inferred from spectroscopy measurements[14]

Methods

Results

Conclusion