NMR studies of the helical antiferromagnetic compound EuCo2P2

Higa, N.; Ding, Q. -P.; Johnston, D. C.; Uehara, H.; Yogi, M.; Furukawa, Y.; Sangeetha, N. S.; Johnston, D. C.; Nakamura, A.; Hedo, M.; Nakama, T.; Onuki, Y.

doi:10.1016/j.physb.2017.09.065

Title: NMR studies of the helical antiferromagnetic compound EuCo₂P₂

Journal Article · 18 September 2017 · Physica. B, Condensed Matter

DOI: https://doi.org/10.1016/j.physb.2017.09.065 · OSTI ID:1435748

Higa, N. ^[1]; Ding, Q. -P. ^[2]; Johnston, D. C. ^[2]; Uehara, H. ^[3]; Yogi, M. ^[3]; Furukawa, Y. ^[2]; Sangeetha, N. S. ^[2]; Johnston, D. C. ^[2]; Nakamura, A. ^[4]; Hedo, M. ^[3]; Nakama, T. ^[3]; Onuki, Y. ^[3]

Ames Lab. and Iowa State Univ., Ames, IA (United States); Univ. of Ryukyus, Okinawa (Japan)
Ames Lab. and Iowa State Univ., Ames, IA (United States)
Univ. of Ryukyus, Okinawa (Japan)
Tokoku Univ., Ibaraki (Japan)

In EuCo₂P₂, 4f electron spins of Eu²⁺ ions order antiferromagnetically below a Neel temperature T_N = 66.5K. The magnetic structure below T_N was reported to be helical with the helix axis along the c-axis from the neutron diffraction study. We report the results of ¹⁵³Eu, ⁵⁹Co and ³¹P nuclear magnetic resonance (NMR) measurements on EuCo₂P₂ using a single crystal and a powdered sample. In the antiferromagnetic (AFM) state, we succeeded in observing ¹⁵³Eu, ⁵⁹Co and ³¹P NMR spectra in zero magnetic field. The sharp ¹⁵³Eu zero field NMR (ZF NMR) lines indicate homogeneous Eu ordered moment. The ⁵⁹Co and ³¹P ZF NMR spectra showed an asymmetric spectral shape, indicating a distribution of the internal magnetic induction at each nuclear position. The AFM propagation vector k characterizing the helical AFM state can be determined from the internal magnetic induction at Co site. In conclusion, we have determined the model-independent value of the AFM propagation vector k distributed from (0, 0, 0.86)2π/c to (0, 0, 0.73)2π/c, where c is the lattice parameter.