From single-molecule magnetism to long-range ferromagnetism in Hpyr[Fe17O16(OH)(12)(py)(12)Br-4]Br-4

C. Vecchini, D. H. Ryan, L. M. D. Cranswick, M. Evangelisti, W. Kockelmann, P. G. Radaelli, A. Candini, M. Affronte, I. A. Gass, E. K. Brechin, O. Moze

Research output: Contribution to journalArticlepeer-review

Abstract

The molecular magnet Hpyr[Fe17O16(OH)(12)(py)(12)Br-4]Br-4 ("Fe-17") has a well-defined cluster spin ground state of S=35/2 at low temperatures and an axial molecular anisotropy of only D similar or equal to -0.02 K. Dipolar interactions between the molecular spins induce long-range magnetic order below 1.1 K. We report here the magnetic structure of Fe-17, as determined by unpolarized neutron diffraction experiments performed on a polycrystalline sample of deuterated Fe-17 in zero applied magnetic field. In addition, we report bulk susceptibility, magnetization, and specific heat data. The temperature dependence of the long-range magnetic order has been tracked and is well accounted for within mean-field theory. Ferromagnetic order along the crystallographic c axis of the molecular spins, as determined by the neutron diffraction experiments, is in agreement with ground-state dipolar energy calculations.

Original languageEnglish
Article number224403
Pages (from-to)-
Number of pages8
JournalPhysical Review B
Volume77
Issue number22
DOIs
Publication statusPublished - Jun 2008

Keywords

  • NEUTRON-DIFFRACTION
  • QUANTUM NANOMAGNET
  • TRANSITION
  • CLUSTER
  • MAGNETIZATION

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