Work

Spin structures and phase diagrams of the spin- 5 2 triangular lattice antiferromagnet Na 2 BaMn ( PO 4 ) 2 under magnetic field

Year: 2025

Type: article

Abstract: We combine single-crystal neutron diffraction studies and Monte Carlo simulations to determine the spin structures and finite-temperature phase diagram of the spin-5/2 triangular-lattice antiferromagnet ${\mathrm{Na}}_{2}\mathrm{BaMn}{({\mathrm{PO}}_{4})}_{2}$ in magnetic field. With the application of a magnetic field in two different directions, namely along the $c$ axis and in the $ab$ plane of the trigonal symmetry, we track the evolution of the spin structure through changes of the magnetic propagation vector. We account for these results with a minimal Heisenberg Hamiltonian that includes easy-axis anisotropy and weak, frustrated interlayer couplings in addition to intralayer exchange. Guided by representation analysis, we refine symmetry-allowed modes to the measured intensities and obtain the spin structures for all field-induced phases, which we compare quantitatively with simulated configurations. Taken together, our measurements and simulations show that frustrated interlayer exchange---rather than purely two-dimensional physics---organizes the unexpectedly rich field-induced phases of ${\mathrm{Na}}_{2}\mathrm{BaMn}{({\mathrm{PO}}_{4})}_{2}$.

Source: Physical review. B./Physical review. B

DOI: 10.1103/kszh-m6bf