Local nuclear and magnetic order in the two-dimensional spin glass Mn0.5Fe0.5PS3

Abstract

© 2020 American Physical Society. We present a comprehensive study of the short-ranged nuclear and magnetic order in the two-dimensional spin glass, Mn0.5Fe0.5PS3. Nuclear neutron scattering data reveal a random distribution of Mn2+ and Fe2+ ions within the honeycomb layers, which gives rise to a spin glass state through inducing competition between neighboring exchange interactions, indicated in magnetic susceptibility data by a cusp at the glass transition, T-g = 35 K. Analysis of magnetic diffuse neutron scattering data collected for both single-crystal and polycrystalline samples gives further insight into the origin of the spin glass phase, with spin correlations revealing a mixture of satisfied and unsatisfied correlations between magnetic moments within the honeycomb planes, which can be explained by considering the magnetic structures of the parent compounds, MnPS3 and FePS3. We found that, on approaching T-g from above, an ensemble-averaged correlation length of xi = 5.5(6)angstrom developed between satisfied correlations, and below T-g, the glassy behavior gave rise to a distance-independent correlation between unsatisfied moments. Correlations between the planes were found to be very weak, which mirrored our observations of rodlike structures parallel to the c* axis in our single-crystal diffraction measurements, confirming the two-dimensional nature of Mn0.5Fe0.5PS3