The structural and magnetic properties of sputter-deposited Fe100−xRux films were studied for x≤50. The crystal structure of Fe100−xRux is shown to be predominantly body-centered cubic for x<13 and to undergo a gradual transition to hexagonal close-packed in the concentration range 13≲x≲20. Magnetic measurements indicate that the addition of Ru induces a noncollinear magnetic order in the body-centered cubic FeRu alloys, while the hexagonal close-packed FeRu alloys exhibit paramagnetic behavior. Increasing the Ru concentration in body-centered cubic FeRu alloys decreases the size of magnetic domains, approaching the size of magnetic grains. A simple atomistic model was used to show that antiferromagnetic coupling of Fe atoms across Ru atoms can be responsible for inducing noncollinear order in the FeRu cubic structures. Magnetic multilayer structures used in thin-film magnetic devices make extensive use of both Fe and Ru layers. Our results reveal that the presence of even a small amount of Ru in Fe influences the magnetic order of Fe, which could impact the performance of these devices.
@article{arxiv.2407.17575,
title = {Transition from ferromagnetic to noncollinear to paramagnetic state with increasing Ru concentration in FeRu films},
author = {Juliana Lisik and Manuel Rojas and Spencer Myrtle and Dominic H. Ryan and René Hübner and Pavlo Omelchenko and Claas Abert and Amil Ducevic and Dieter Suess and Ivan Soldatov and Rudolf Schaefer and Johannes Seyd and Manfred Albrecht and Erol Girt},
journal= {arXiv preprint arXiv:2407.17575},
year = {2024}
}