Spin phase detection by spin current in a chiral helimagnet

TL;DR

This paper demonstrates electrical detection of the spin phase in a nanoscale chiral helimagnet using nonlocal spin valve measurements, linking surface magnetic moments to spin currents for potential spintronic applications.

Contribution

It introduces a method to detect the spin phase electrically in a van der Waals helimagnet via spin currents, supported by experimental data and micromagnetic simulations.

Findings

Surface magnetic moments correlate with spin currents.

Magnetic field dependence matches surface magnetic structure.

Detection method applicable to nanoscale spintronic devices.

Abstract

Helimagnets, characterized by a helical arrangement of magnetic moments, possess unique internal degrees of freedom, including the spin phase, defined by the phase of the helical magnetic structure. Electrical detection of the spin phase is essential for both practical applications and fundamental research in helimagnets. Here, we demonstrate the electrical detection of the spin phase in a van der Waals nanoscale chiral helimagnet CrNb$_3$S$_6$ using nonlocal spin valve measurements. Due to the short spin diffusion length in CrNb$_3$S$_6$ ($\sim5$~nm), the surface magnetic moment direction, which corresponds to the spin phase, can be detected via spin currents. The experimentally observed magnetic field dependence of the nonlocal spin valve signal is consistent with that of the surface magnetic moment in the helical magnetic structure, as supported by micromagnetic simulations. Our results establish spin currents as a powerful tool for detecting the spin phase in helimagnets, opening avenues for utilizing the spin phase as a novel internal degree of freedom in nanoscale spintronic devices.