Investigation of the spin-1 honeycomb antiferromagnet BaNi2V2O8 with easy-plane anisotropy

Abstract

The magnetic properties of the two-dimensional, S=1 honeycomb antiferromagnet BaNi2V2O8 have been comprehensively studied using DC susceptibility measurements and inelastic neutron scattering techniques. The magnetic excitation spectrum is found to be dispersionless within experimental resolution between the honeycomb layers, while it disperses strongly within the honeycomb plane where it consists of two gapped spin-wave modes. The magnetic excitations are compared to linear spin-wave theory allowing the Hamiltonian to be determined. The first-and second-neighbour magnetic exchange interactions are antiferromagnetic and lie within the ranges 10.90meV≤Jn≤13.35 meV and 0.85meV≤Jnn≤1.65 meV respectively. The interplane coupling Jout is four orders of magnitude weaker than the intraplane interactions, confirming the highly twodimensional magnetic behaviour of this compound. The sizes of the energy gaps are used to extract the magnetic anisotropies and reveal substantial easy-plane anisotropy and a very weak in-plane easy-axis anisotropy. Together these results reveal that BaNi2V2O8 is a candidate compound for the investigation of vortex excitations and Berezinsky-Kosterliz-Thouless phenomenona.

Topological magnon nodal lines and absence of magnon spin Nernst effect in layered collinear antiferromagnets

“…For ferromagnetic interlayer coupling J c < 0, there is only one single doubly-degenerate magnon band. However, for antiferromagnetic interlayer coupling J c > 0, there are two non-degenerate magnon branches as confirmed experimentally in the layered honeycomb antiferromagnetic materials CaMn 2 Sb 2 [44] and BaNi 2 V 2 O 8 [45]. We do not consider the ferromagnetic interlayer coupling as it is similar to 2D honeycomb antiferromagnets [35,36], which is topologically trivial.…”

Featureless quantum paramagnet with frustrated criticality and competing spiral magnetism on spin-1 honeycomb lattice magnet

“…A series of materials have been proposed as spin-1 honeycomb lattice magnets [41][42][43][44][45][46][47]. These include the layer honeycomb material BaNi 2 (X O 4 ) 2 (X = V, P, and As), the buckled honeycomb material Ba 2 NiTeO 6 , Na and develop a Néel order.…”

Signatures for Berezinskii-Kosterlitz-Thouless critical behavior in the planar antiferromagnet BaNi2V2O8

“…Here, we report a comprehensive investigation of the spin-1 honeycomb compound BaNi 2 V 2 O 8 , which was recently discovered to be a rare physical realization of the 2D Heisenberg antiferromagnet (AFM) with weak XY anisotropy and negligible interlayer coupling [26,27]. Using a combination of experimental and theoretical techniques we (i) establish a consistent phase diagram of BaNi 2 V 2 O 8 , (ii) identify the temperature range over which it behaves as a 2D XY magnet, and (iii) provide signatures of BKT scaling behavior driven by vortices in BaNi 2 V 2 O 8 within the 2D XY regime above T N .…”

“…The following Hamiltonian of BaNi 2 V 2 O 8 was extracted by comparing neutron scattering spectra to a spin-wave theory analysis [27]:…”