Probing the YD3 structure by H-2 NMR electric-field gradients: A comparison with first-principles calculations



: Zogal OJ, Wolf W, Herzig P, Vuorimaki AH, Ylinen EE, Vajda P

Publisher: AMERICAN PHYSICAL SOC

: 2001

Physical Review B

PHYSICAL REVIEW B

: PHYS REV B

: 64

: 21

: art. no.

: 214110

: 7

: 0163-1829

DOI: https://doi.org/10.1103/PhysRevB.64.214110


Electric-field gradients (EFG's) in yttrium trideuteride (YD2.98) have been determined using deuteron magnetic resonance (DMR) and compared with values for the P (3) over barc 1 and P6(3)cm structures calculated from first principles. The experimental DMR spectra at low temperatures (180-290 K) could be decomposed into two components with intensity ratio 2:1 in accordance with the expected two groups of deuterium sites, i.e., tetrahedral and octahedral sites in the crystal lattice. Their characteristic quadrupole frequencies, nu (q), and asymmetry parameters, eta, have been compared with the theoretical values obtained for the structures with space groups P (3) over bar c1 (no. 165) and P6(3)cm (no. 185). The agreement between the experimental and calculated results is such better for the latter structure. The spectra at higher temperatures (300-370 K) transform from a two-component configuration into three quadrupolar doublets plus a low-intensity narrow central component. One of the doublets keeps the same parameters as those observed at low temperatures. The two others indicate changes in the tetrahedral site environments. One possible explanation could be a thermally activated quasi-two-dimensional hopping of the D atoms to nearby sites within the ab plane.



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