Incommensurate magnet iron monophosphide FeP: Crystal growth and characterization

Abstract

We report an optimized chemical vapor transport method, which allows growing FeP single crystals up to 500 mg in mass and 80 mm 3 in volume. The high quality of the crystals obtained by this method was confirmed by means of EDX, high-resolution TEM, low-temperature single crystal XRD and neutron diffraction experiments. We investigated the transport and magnetic properties of the single crystals and calculated the electronic band 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 TN =119 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 Q = (0, 0, ±δ), where δ ≈ 0.2.For the full understanding of the magnetic state, further experiments are needed. The successful growth of large high-quality single crystals opens the opportunity for further investigations of itinerant magnets with incommensurate spin structures using a wide range of experimental tools.

Topologically-Driven Linear Magnetoresistance in Helimagnetic FeP

“…We assumed a paramagnetic configuration because of the small magnetic moment [3], which is a consequence of the octahedral crystal field that inverts the 4s and 3d energetic levels and changes the Fe configuration from commonly observed d 6 to d 8 . The band structure is similar to that recently reported [33], though our Fermi level appears to be at a slightly lower energy, which somewhat alters the appearance of the Fermi surface. The nonsymmorphic symmetry of the MnP-type structure implies the presence of several linear bands and semi-Dirac points.…”

Lattice dynamics in the double-helix antiferromagnet FeP

“…High quality single crystals of FeP up to 500 mg in mass and 80 mm 3 in volume were grown by chemical vapor transport with iodine as a transport agent. The quality of the crystals were confirmed by means of EDX, XRD, magnetic, transport, high resolution TEM and single-crystal neutron diffraction experiments [36]. The temperature dependence of the resistivity shows the typical metallic behavior with a residual resistivity ratio RRR = 566.…”

“…The temperature dependence of the resistivity shows the typical metallic behavior with a residual resistivity ratio RRR = 566. Below the the Néel temperature T N = 119.3 K, analysis of the neutron diffraction data yields an incommensurate magnetic structure with the propagation vector Q = (0, 0, ±δ), where δ ≈ 0.2 [1,36]. For neutron spectroscopy measurements, we used a single crystal with a mass of ∼0.5 g.…”

“…It is described by the space group P nma (no. 62) with the lattice parameters a = 5.197 Å, b = 3.099 Å, and c = 5.794 Å at room temperature[1,36]. Both Fe and P occupy the 4c Wyckoff position with the parameters x = 0.002 and z = 0.200 for Fe and x = 0.191 and z = 0.569 for P. It is worth noting that the P nma crystal structure of FeP can be considered as a distorted hexagonal NiAs-type structure (P6 3 /mmc space group), where the distorted hexagonal layers of Fe ions are stacked along the orthorhombic a-axis.…”

Frustration model and spin excitations in the helimagnet FeP

“…Figures 3(a)-3(c) summarize the main features of the magnetic spectra of FeP at a temperature of 7.5 K. The previous neutron diffraction measurements on single crystals [20,36], as well as our powder neutron diffraction data shown in the Supplemental Materials [37] showed that the helical magnetic structure yields pairs of strong magnetic satellites at the momenta (1 1 0) ±k and (1 0 1) ±k, where k = (0 0 0.2) r.l.u. The elastic (E = 0) slice through the dataset in the vicinity of the momentum transfer Q = (1 1 0), which is a forbidden Bragg reflection for the nuclear structure, is shown in Fig.…”