Frustration on a centered pyrochlore lattice in metal-organic frameworks

Geometric frustration inhibits magnetic systems from ordering, opening a window to unconventional phases of matter. The paradigmatic frustrated lattice in three dimensions host spin liquid is the pyrochlore, although there remain few experimental compounds thought realize such state. Here we go beyond pyrochlore via molecular design metal-azolate framework [Mn(II)(ta)$_2$], which realizes closely related centred Mn-spins with $S=5/2$. Despite Curie-Weiss temperature $-21$ K indicating energy scale interactions, [Mn(II)(ta)$_2$] orders at only 430 mK, putting it firmly category highly magnets. Comparing magnetization and specific heat measurements numerical results for minimal Heisenberg model, predict that this material displays distinct features classical structure factor reflecting Coulomb physics presence charges.