Anisotropy-governed competition of magnetic phases in the honeycomb quantum magnet Na3Ni2SbO6 studied by dilatometry and high-frequency ESR

作者：Werner J; Hergett W; Gertig M; Park J; Koo C; Klingeler R^*

来源：PHYSICAL REVIEW B, 2017, 95(21): 214414.

DOI：10.1103/PhysRevB.95.214414

Thermodynamic properties and low-energy magnon excitations of S = 1 honeycomb-layered Na3Ni2SbO6 have been investigated by high-resolution dilatometry, static magnetization, and high-frequency electron spin resonance studies in magnetic fields up to 16 T. At T-N = 16.5 K, there is a tricritical point separating two distinct antiferromagnetic phases, AF1 and AF2, from the paramagnetic regime. In addition, our data imply short-range antiferromagnetic correlations at least up to similar to 5T(N). Well below T-N, the magnetic field B-C1 approximate to 9.5 T is needed to stabilize AF2 against AF1. The thermal expansion and magnetostriction anomalies at T-N and B-C1 imply significant magnetoelastic coupling, both of which are associated with a sign change of partial derivative L/partial derivative B. The transition at B-C1 is associated with softening of the antiferromagnetic resonance modes observed in the electron-spin-resonance spectra. The anisotropy gap Delta = 360 GHz implies considerable uniaxial anisotropy. We deduce the crucial role of axial anisotropy favoring the AF1 spin structure over the AF2 one. While the magnetostriction data disprove a simple spin-flop scenario at BC1, the nature of a second transition at B-C2 approximate to 13 T remains unclear. Both the sign of the magnetostriction and Gruneisen analysis suggest that the short-range correlations at high temperatures are of AF2 type.

• 出版日期2017-6-20