• DOI:10.1103/PHYSREVB.102.214416
• Corpus ID: 221292926

NMR study of magnetic structure and hyperfine interactions in the binary helimagnet FeP

@article{Gippius2020NMRSO,
  title={NMR study of magnetic structure and hyperfine interactions in the binary helimagnet FeP},
  author={Andrey A. Gippius and Alexey V. Tkachev and S. V. Zhurenko and Avinash V. Mahajan and Norbert B{\"u}ttgen and M. Schaedler and I. O. Chernyavskii and Igor V. Morozov and Saicharan Aswartham and Bernd B{\"u}chner and Alexander S. Moskvin},
  journal={Physical Review B},
  year={2020}
}

• A. Gippius, A. Tkachev, +8 authors A. Moskvin
• Published 25 August 2020
• Physics
• Physical Review B

The main goal of our work was to determine and explore the field dependent transformation of the magnetically ordered helical structure in FeP. The zero-field NMR spectrum for the polycrystalline sample can be easily explained assuming an incommensurate spiral ordering of Fe magnetic moments with a dominating contribution to the local field at the phosphorus nucleus from the Fe - ${}^{31}$P transferred hyperfine interactions.
The NMR lineshape of the FeP powder sample gradually changes with increasing field from the trapezoidal-like shape at low fields to a pronounced double-horn shape at highest field. The observed transformation of our ${}^{31}$P NMR spectra of FeP provides strong evidence of the spin-reorientation of the spin-flop type in FeP which occurs in the range of external fields $4 < \mu_0 H < 5$ T confirmed also by specific-heat measurements.
The single-crystal ${}^{31}$P NMR spectra for external magnetic fields directed within the ($ac$)-plane exhibit a pronounced four-peak structure characteristic of an incommensurate helimagnetic ground state with two pairs of magnetically inequivalent phosphorus positions. These spectra were successfully simulated assuming a simple planar helix of Fe magnetic moments in the ($ab$)-plane with a phase shift of 36 degrees between Fe1-Fe3 and Fe2-Fe4 sites according to data from neutron scattering. Theoretical estimations of the transferred hyperfine coupling provide an excellent quantitative description of the observed angular dependences for the peak-to-Larmor field separations. Rotational single-crystal NMR experiments in high fields ($\nu_{L}$ (${}^{31}$P) = 140 MHz) reveal an effect of varying phosphorous local fields distribution caused by an iron spin-reorientation transition in high magnetic field.