Spin pumping and magnetization dynamics in ferromagnet-Luttinger liquid junctions

TL;DR

This paper investigates how electron interactions in a Luttinger liquid suppress spin pumping and damping in ferromagnet-Luttinger liquid junctions, revealing power-law temperature dependence and analyzing magnetization dynamics.

Contribution

It demonstrates the suppression of spin pumping and damping due to interactions in Luttinger liquids and derives their temperature dependence, extending understanding of spin transport in such systems.

Findings

Spin pumping/damping is suppressed by interactions in Luttinger liquids.

The suppression exhibits a power-law temperature dependence.

Derived effective equations for magnetization dynamics in ferromagnet-Luttinger liquid systems.

Abstract

We study spin transport between a ferromagnet with time-dependent magnetization and a conducting carbon nanotube or quantum wire, modeled as a Luttinger liquid. The precession of the magnetization vector of the ferromagnet due for instance to an outside applied magnetic field causes spin pumping into an adjacent conductor. Conversely, the spin injection causes increased magnetization damping in the ferromagnet. We find that, if the conductor adjacent to the ferromagnet is a Luttinger liquid, spin pumping/damping is suppressed by interactions, and the suppression has clear Luttinger liquid power law temperature dependence. We apply our result to a few particular setups. First we study the effective Landau-Lifshitz-Gilbert (LLG) coupled equations for the magnetization vectors of the two ferromagnets in a FM-LL-FM junction. Also, we compute the Gilbert damping for a FM-LL and a FM-LL-metal junction.