The magnetic properties of the molecular cluster Mn12Ac are due to the four Mn3+ ions that have spins S=3/2 and the eight Mn4+ ions with spins S=2. These spins are coupled by an exchange mechanism. We determine the four exchange couplings assuming a Heisenberg-type interaction between the ions. We use exact diagonalization of the spin Hamiltonian by a Lanczos algorithm and we adjust the couplings to reproduce the magnetization curve of Mn12Ac. We also impose the constraint of reproducing a gap of 35 K between an S=10 ground state and a first excited state with S=9. We predict that there is an excited level with S=8 at 37 K above the ground state, only slightly above the S=9 excited state that lies at 35 K and the next excited state is an S=9 multiplet at 67 K above the S=10 ground state.
EXCHANGE COUPLING IN THE MAGNETIC MOLECULAR CLUSTER MN12AC / REGNAULT N.; JOLICOEUR T.; R. SESSOLI; GATTESCHI D.; VERDAGUER M.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - STAMPA. - 66:(2002), pp. 054409-054409. [10.1103/PhysRevB.66.054409]
EXCHANGE COUPLING IN THE MAGNETIC MOLECULAR CLUSTER MN12AC
SESSOLI, ROBERTA;GATTESCHI, DANTE;
2002
Abstract
The magnetic properties of the molecular cluster Mn12Ac are due to the four Mn3+ ions that have spins S=3/2 and the eight Mn4+ ions with spins S=2. These spins are coupled by an exchange mechanism. We determine the four exchange couplings assuming a Heisenberg-type interaction between the ions. We use exact diagonalization of the spin Hamiltonian by a Lanczos algorithm and we adjust the couplings to reproduce the magnetization curve of Mn12Ac. We also impose the constraint of reproducing a gap of 35 K between an S=10 ground state and a first excited state with S=9. We predict that there is an excited level with S=8 at 37 K above the ground state, only slightly above the S=9 excited state that lies at 35 K and the next excited state is an S=9 multiplet at 67 K above the S=10 ground state.File | Dimensione | Formato | |
---|---|---|---|
PhysRevB_2002.pdf
Accesso chiuso
Descrizione: PhysRevB_2002
Tipologia:
Pdf editoriale (Version of record)
Licenza:
Tutti i diritti riservati
Dimensione
288.39 kB
Formato
Adobe PDF
|
288.39 kB | Adobe PDF | Richiedi una copia |
I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.