Vacuum fluctuations and the spin current in mesoscopic structures with collinear magnetic order

TL;DR

This paper demonstrates that quantum vacuum fluctuations can induce a nonzero equilibrium spin current in mesoscopic magnetic structures with collinear order, driven by anisotropy orientation variations.

Contribution

It reveals a novel mechanism where quantum vacuum fluctuations generate equilibrium spin currents in magnetic nanostructures with uniform magnetic order.

Findings

Equilibrium spin current can exist in magnetic rings with uniform magnetization.

Quantum vacuum fluctuations are responsible for spin current generation.

The effect is linked to anisotropy axis variations inducing spin torque.

Abstract

We show that in magnetic nanostructures with a homogeneous magnetic order, the equilibrium spin current can be nonzero. For example, this is the case of a wide magnetic ring with the magnetization along the ring axis. The physical reason of this effect is a variation of the orientation of anisotropy axis inducing a spin torque acting on the magnetic ions. The mechanism of the spin current generation is related to the quantum vacuum fluctuations in the magnetic system.