High quality epitaxial thin films and exchange bias of antiferromagnetic Dirac semimetal FeSn

TL;DR

This paper reports the successful synthesis of high-quality epitaxial FeSn films, demonstrating significant exchange bias effects and paving the way for exploring topological physics and spintronics applications in antiferromagnetic Dirac semimetals.

Contribution

It introduces a simple method to fabricate epitaxial FeSn films and heterostructures, enabling further research into their topological and magnetic properties.

Findings

Large exchange bias of 220 Oe at 5 K in FeSn/Py heterostructures

Successful synthesis of high-quality epitaxial FeSn films via magnetron sputtering

Evidence of complex magnetic interactions and anisotropy in FeSn films

Abstract

FeSn is a topological semimetal (TSM) and kagome antiferromagnet (AFM) composed of alternating Fe3Sn kagome planes and honeycomb Sn planes. This unique structure gives rise to exotic features in the band structures such as the coexistence of Dirac cones and flatbands near the Fermi level, fully spin-polarized 2D surface Dirac fermions, and the ability to open a large gap in the Dirac cone by reorienting the N\'eel vector. In this work, we report the synthesis of high quality epitaxial (0001) FeSn films by magnetron sputtering. Using FeSn/Py heterostructures, we show a large exchange bias effect that reaches an exchange field of 220 Oe at 5 K, providing unambiguous evidence of antiferromagnetism and strong interlayer exchange coupling in our films. Field cycling studies show steep initial training effects, highlighting the complex magnetic interactions and anisotropy. Importantly, our work provides a simple, alternative means to fabricate FeSn films and heterostructures, making it easier to explore the topological physics of AFM TSMs and develop FeSn-based spintronics.