Incommensurate magnet iron monophosphide FeP: Crystal growth and characterization

We report an optimized chemical vapor transport method that enables the growth of FeP single crystals up to 500 mg in mass and $80\phantom{\rule{0.16em}{0ex}}{\mathrm{mm}}^{3}$ in volume. The high quality of the crystals obtained by this method was confirmed by means of energy-dispersive x-ray spectroscopy, high-resolution transmission electron microscopy, low-temperature single-crystal x-ray diffraction, and neutron diffraction experiments. We investigated the transport and magnetic properties of the single crystals, and we calculated the electronic structure of FeP. We show both theoretically and experimentally that the ground state of FeP is metallic. The examination of the magnetic data reveals antiferromagnetic order below ${T}_{\mathrm{N}}=119\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ while transport remains metallic in both the paramagnetic and the antiferromagnetic phase. The analysis of the neutron diffraction data shows an incommensurate magnetic structure with the propagation vector $\mathbf{Q}=(0,0,\ifmmode\pm\else\textpm\fi{}\ensuremath{\delta})$, where \ensuremath{\delta} is close to 0.2. For a full understanding of the magnetic state, further experiments are needed. The successful growth of large high-quality single crystals paves the way for further investigations of itinerant magnets with incommensurate spin structures using a wide range of experimental tools.