Abstract. Frustrated itinerant ferromagnets, with non-collinear static spin structures, are an exciting class of material as their spin chirality can introduce a Berry phase in the electronic scattering and lead to exotic electronic phenomena such as the anomalous Hall effect (AHE).

This study presents a reexamination of the magnetic properties of Fe₃Sn₂, a metallic ferromagnet, based on the two-dimensional kagome bilayer structure. Previously thought of as a conventional ferromagnet, we show using a combination of SQUID (superconducting quantum interference device) measurements, symmetry analysis and powder neutron diffraction that Fe₃Sn₂ is a frustrated ferromagnet with a temperature-dependent non-collinear spin structure. The complexity of the magnetic interactions is further evidenced by a re-entrant spin glass transition ( K) at temperatures far below the main ferromagnetic transition (T_C = 640 K).

Fe₃Sn₂ therefore provides a rare example of a frustrated itinerant ferromagnet. Further, as well as being of great fundamental interest our studies highlight the potential of Fe₃Sn₂ for practical application in spintronics technology, as the AHE arising from the ferromagnetism in this material is expected to be enhanced by the coupling between the conduction electrons and the non-trivial magnetic structure over an exceptionally wide temperature range.

Print publication: Issue 45 (11 November 2009)
Received 31 July 2009, in final form 11 September 2009
Published 9 October 2009