Quantum Dynamics of Spin Wave Propagation Through Domain Walls

TL;DR

This paper investigates quantum spin wave interactions with domain walls in magnetic chains, revealing that domain walls transmit only the longitudinal spin component and highlighting limitations of classical models for microscopic systems.

Contribution

It provides a quantum mechanical analysis of spin wave and domain wall interactions, demonstrating the limitations of classical models like LLG in microscopic magnetic systems.

Findings

Domain walls remain stable when interacting with spin waves.

Only the longitudinal component of spin excitations is transmitted.

Classical LLG models are inadequate for microscopic spin wave-domain wall interactions.

Abstract

Through numerical solution of the time-dependent Schrodinger equation, we demonstrate that magnetic chains with uniaxial anisotropy support stable structures, separating ferromagnetic domains of opposite magnetization. These structures, domain walls in a quantum system, are shown to remain stable if they interact with a spin wave. We find that a domain wall transmits the longitudinal component of the spin excitations only. Our results suggests that continuous, classical spin models described by LLG equation cannot be used to describe spin wave-domain wall interaction in microscopic magnetic systems.