Nanomechanical Detection of Itinerant Electron Spin Flip

TL;DR

This paper reports the direct measurement of spin-induced mechanical torque from itinerant electrons using a nanoscale torsion oscillator, revealing new insights into electron spin dynamics and potential applications in spintronics and precision force measurements.

Contribution

It introduces a novel experimental approach to directly measure spin-induced torque from itinerant electrons at the nanoscale.

Findings

Achieved torque sensitivity of 10^{-22} N·m/√Hz.

Demonstrated direct measurement of electron spin polarization.

Potential applications in spintronics and fundamental physics.

Abstract

Spin is an intrinsically quantum property, characterized by angular momentum. A change in the spin state is equivalent to a change in the angular momentum or mechanical torque. This spin-induced torque has been invoked as the intrinsic mechanism in experiments ranging from the measurements of angular momentum of photons g-factor of metals and magnetic resonance to the magnetization reversal in magnetic multi-layers A spin-polarized current introduced into a nonmagnetic nanowire produces a torque associated with the itinerant electron spin flip. Here, we report direct measurement of this mechanical torque and itinerant electron spin polarization in an integrated nanoscale torsion oscillator, which could yield new information on the itinerancy of the d-band electrons. The unprecedented torque sensitivity of 10^{-22} N m/ \sqrt{Hz} may enable applications for spintronics, precision measurements of CP-violating forces, untwisting of DNA and torque generating molecules.