Microfluidic Actuation by Einstein-de Haas Spin Torque

Xin Hu; Mamoru Matsuo

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arXiv · 2605.25387

Microfluidic Actuation by Einstein-de Haas Spin Torque

Xin Hu·Mamoru Matsuo

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Abstract

We propose spin-current microfluidic actuation of a sealed liquid metal. Spin angular momentum injected from Pt contacts enters the liquid as an Einstein-de Haas torque and is converted through micropolar angular-momentum balance into viscous flow without pressure drive, moving walls, magnetic fields, Lorentz forces, or charge flow through the liquid. The dc velocity obeys universal spin-diffusion scaling, and the finite-frequency spin-mechanical admittance resolves viscous momentum diffusion, spin transport, microrotation relaxation, and interface transparency of the liquid-metal channel.

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Xin Hu, Mamoru Matsuo. 2026-05-25. Microfluidic Actuation by Einstein-de Haas Spin Torque. https://arxiv.org/abs/2605.25387

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