Experimental study of the in-plane Hall effect in a ferromagnetic Weyl semimetal*

Material realizations of the kagome lattice with strong spin orbit coupling and ferromagnetism have emerged as a promising platform to search for novel topological phases. The combination of large magnetization-induced Zeeman terms, symmetry-breaking, and kagome lattice-derived Dirac electronic states in these materials provide the framework for a large electronic Berry curvature. This can give rise to novel Hall effects, such as the in-plane Hall effect.

We present results from electrical transport measurements on Fe₃Sn, a Weyl semimetal with strong in-plane ferromagnetism and a Curie temperature much above room temperature. Epitaxial Fe₃Sn thin films were prepared using molecular beam epitaxy and shaped into circular Hall bar devices. Conducting in- and out-of-plane Hall measurements, this Hall bar geometry enables us to completely characterize the 4π angular dependence of the transport properties as a function of temperature and magnetic field. We discuss our experimental observations in terms of a Berry curvature-induced in-plane Hall effect and compare them with results from ab-initio and model calculations.