Gilbert damping of [Co/Pd]n/Py multilayer thin films

TL;DR

This study investigates how Gilbert damping varies with temperature and layer repetitions in [Co/Pd]n/Py multilayer films, revealing multiple damping contributions and the impact of two-magnon scattering on magnetic relaxation.

Contribution

It provides a detailed experimental analysis of temperature-dependent Gilbert damping and identifies three distinct damping mechanisms in multilayer films.

Findings

Gilbert damping increases as temperature decreases from 300K to 50K.

Two-magnon scattering intensity grows with more Co/Pd repetitions.

Multiple damping contributions are independently identified.

Abstract

Understanding the Gilbert damping in exchange-coupled multilayer materials is particularly important to develop future fast switching spintronics devices. Here, we report an experimental investigation of temperature-dependent Gilbert damping in [Co/Pd]n/Py multilayer films of varying the number of Co/Pd repetitions by ferromagnetic resonance. The results demonstrate that three independent contributions to the Gilbert damping are identified, namely the intrinsic Gilbert damping, the inhomogeneous linewidth broadening and the two-magnon scattering contribution. Of particular interest, the two-magnon scattering intensity increases as the enlargement of number repetitions of Co/Pd due to the larger pinning effect at the interface between Py and the Co/Pd layers. The Gilbert damping increases monotonically as the temperature decreases from 300K to 50K. Our findings open the door to comprehend the physical origin of the Gilbert damping in ultrathin exchange-coupled multilayer films.