Anisotropic exchange interactions in [LnFe] dinuclear systems: Magnetometry, dual mode X-band Electron Paramagnetic Resonance, and Mössbauer spectroscopic studies

Albert Figuerola, Vassilis Tangoulis*, Yiannis Sanakis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

An experimental and theoretical procedure is introduced in order to calculate the magnitude and anisotropy of interaction between a lanthanide and a 3d-metal ion. The general formula of the molecular compounds is [Ln(H2O)3(dmf)4(μ-CN)Fe-(CN) 5] · nH2O, where 1 ≤ n ≤ 1,5 and dmf = N,N′-dimethylformamide, abbreviated as [LnFe] from now on. The main parts of this procedure are (a) the evaluation of the effective g-parameters of the lanthanide ion with the help of EPR measurements; (b) the use of dual-mode EPR spectroscopy to define the anisotropic exchange interactions with the help of an anisotropic Hamiltonian model; (c) use of the same magnetic model to fit magnetization and susceptibility data in order to verify the EPR findings; and (d) introduction of a supportive technique, in our case Mössbauer spectroscopy due to the presence of the Fe ion. It was possible to define some trends concerning the exchange components of the [CeFe] dimer according to which the isotropic exchange constant is smaller than 2 cm-1 and the anisotropic components are [D, E] = [0.06(1), 0.05(1)] cm-1. Using EPR spectrosopy it was possible to prove that the [PrFe] and [EuFe] dimers have negligible interactions. For the case of [PrFe], using appropriate magnetic models the energy difference between the ground state Γ1 and the excited Γ3, Γ4 and Γ5 were calculated and found to be Δ31 = 293(5) cm-1, Δ41 = 76(5) cm-1 and Δ51 = 232(5) cm-1. For the case of [EuFe], the spin-orbit coupling parameter was found to be λ = 340 cm-1.

Original languageEnglish (US)
Pages (from-to)204-215
Number of pages12
JournalChemical Physics
Volume334
Issue number1-3
DOIs
StatePublished - Apr 20 2007

Keywords

  • Anisotropic exchange interaction
  • Dual mode EPR
  • Lanthanides

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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