We report on the magnetic properties of {Cr10} wheels (Cr10(OMe)20(O2CCMe)10) UHV-sublimated on Cu(111) and Au(111) single-crystals investigated by means of by XAS & XMCD, SQUID magnetometry and STM. We discuss the magnetic anisotropy and magnetic moment field-dependence of the grafted {Cr10} molecules, as a function of the metallic substrate and layer thickness, and compare it with bulk material. Our results demonstrate that evaporated molecules show negligible anisotropy and weak dependence with the substrate. A combination of XMCD and SQUID magnetometry show that Mono- and Multi-layer {Cr10} samples exhibit a magnetic behavior stemming from a S = 9 ground state, ruling out some previous results. Montecarlo simulations show that the magnetic bulk ground state can be explained by {Cr10} molecules magneticaly consisting of two semicrowns containing 4 Cr ions interacting ferromagnetically, separated by 2 Cr ions with antiferromagnetic interactions, giving rise to the ground S = 9 state, in agreement with previous EPR data in literature. Evaporation of {Cr10} onto a substrate producing subtle structural changes induce strong changes in the Cr-Cr interactions and distinct magnetic behavior from the bulk, probably stabilizing S = 0 ground state.

Resumen del trabajo presentado a la 21st International Conference on Solid Compounds of Transition Elements (SCTE), celebrada en Viena (Austria) del 25 al 29 de marzo de 2018.

Peer Reviewed