Magnetic and Transport Properties of Epitaxial Thin Films of Kagome Ferrimagnet RMn₆Sn₆ (R = Er, Tb)

Kagome ferrimagnets RMn₆Sn₆ family is a highly tunable system for studying the interplay between magnetism and non-trivial band structures (e.g., Dirac cones, flat bands). In particular, a large intrinsic anomalous Hall effect has been demonstrated in out-of-plane magnetized TbMn₆Sn₆ bulk crystals, making it a promising candidate material for realizing high-temperature quantum anomalous Hall effect. Looking forward, the growth of RMn₆Sn₆ thin films is highly desired for both research and applications. Here we discuss the molecular beam epitaxy (MBE) growth, magnetic properties, and transport properties of ErMn₆Sn₆ and TbMn₆Sn₆ thin films. The ErMn₆Sn₆ and TbMn₆Sn₆ thin films are grown on Pt(111) buffer layers using atomic-layer MBE. The structures of the thin films are confirmed by a combination of reflection-high energy electron diffraction (RHEED), X-ray diffraction (XRD), and atomic force microscopy (AFM). Our SQUID measurements show that TbMn₆Sn₆ thin films have uniaxial anisotropy below room temperature, while ErMn₆Sn₆ thin films favor in-plane magnetization. We have also developed a semiclassical theory based on the Fuchs-Sondheimer model to analyze the transport properties of RMn₆Sn₆/Pt bilayers.