From magnetic order to spin-liquid ground states on the S=32 triangular lattice

Abstract

The series of compounds, AAg 2 Cr[VO 4 ] 2 with A = Ag, K, or Rb, are layered S = 3/2 triangularlattice (TL) systems where the magnetic exchange interactions between Cr 3+ (3d 3 ) ions are mediated by non-magnetic [VO 4 ] 3− entities. Here, the relative orientation of the vanadate is altered with respect to the TL as a function of the A-site which corresponds to an induced symmetry change of the [CrO 6 ]-complex. All members of this series of compounds belong to the class of frustrated TL antiferromagnets. We find that the distorted TL (A = Ag) exhibits collinear antiferromagnetic long-range order (LRO) at T N ≈ 10 K, whereas the high-symmetry cases (A = K, Rb) evade LRO in zero field down to 0.03 K, the lowest temperature of our experiments. The latter members of the series belong to the undistorted TL and are candidates for spin-liquid ground states presumably not related to Ising anisotropy or dimerization.

Unconventional spin excitations in the S=32 triangular antiferromagnet RbAg2Cr[VOLee1, Klauer2, Menten3 et al. 2020Phys. Rev. BSelf Cite7060View full textAdd to dashboardCite

“…We observe no muon precession or missing initial polarization down to 25 mK, defying the occurrence of long-range magnetic ordering. This observation is fully consistent with the neutron diffraction data and thermodynamic results [17].…”

“…Polycrystalline samples of RbAg 2 Cr[VO 4 ] 2 were synthesized by solid-state reactions as described in Ref. [17]. The sample quality was characterized by Rietveld refinements of x-ray diffraction data [Stoe STADIP diffractometer, Mo Kα 1 , T = 295 K, space group P3, Z = 1, a = 5.4557(2) Å, c = 7.3791(3) Å].…”

“…For A = Ag + collinear long-range magnetic order (T N = 10 K) is observed. In contrast, the absence of LRO down to 30 mK is reported for A = Rb + [17]. The latter intriguing observation places RbAg 2 Cr[VO 4 ] 2 as a candidate for a QSL ground state.…”

“…1(a)]. The orientation of these moments within this plaquette was derived from neutron diffraction experiments [17]. The plaquette's corners mark the oxygen positions of the Cr coordination.…”

Reactivity and Structural Defects in Glaserite‐Type Iron‐Vanadates

“…In recent years the 3d‐transition metal compounds have triggered interest as these present examples for magnetic triangular lattices with ferromagnetic, antiferromagnetic, or spin‐liquid like ground states. From substitution variants on the M site by diamagnetic ions or defect vacancies, ratio M :( M ′ or □) = 2:1, honeycomb lattices may be obtained , .…”