Temperature-dependent Gilbert damping of Co2FeAl thin films with different degree of atomic order

TL;DR

This study investigates how temperature affects Gilbert damping in Co2FeAl thin films with varying atomic order, revealing that well-ordered films exhibit ultralow damping due to combined electron scattering mechanisms.

Contribution

It provides new insights into the temperature-dependent Gilbert damping mechanisms in full Heusler alloy thin films, emphasizing the role of atomic order.

Findings

Well-ordered Co2FeAl films show ultralow room temperature damping.

Damping mechanisms differ between well-ordered and disordered phases.

Inter- and intraband scattering govern damping in well-ordered films.

Abstract

Half-metallicity and low magnetic damping are perpetually sought for in spintronics materials and full Heusler alloys in this respect provide outstanding properties. However, it is challenging to obtain the well-ordered half-metallic phase in as-deposited full Heusler alloys thin films and theory has struggled to establish a fundamentals understanding of the temperature dependent Gilbert damping in these systems. Here we present a study of the temperature dependent Gilbert damping of differently ordered as-deposited Co2FeAl full Heusler alloy thin films. The sum of inter- and intraband electron scattering in conjunction with the finite electron lifetime in Bloch states govern the Gilbert damping for the well-ordered phase in contrast to the damping of partially-ordered and disordered phases which is governed by interband electronic scattering alone. These results, especially the ultralow room temperature intrinsic damping observed for the well-ordered phase provide new fundamental insights to the physical origin of the Gilbert damping in full Heusler alloy thin films.