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Sharmin, Sonia; Ardavan, Arzhang; Blundell, Stephen J.; Rival, Olivier; Goy, P.; McInnes, Eric J. L.; Low, David M.

doi:10.1103/physrevb.73.214433

Cited by 1 publication

(9 citation statements)

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“…The C(T) curve shows a typical Schottky shape, which is reasonably well fitted under the single-cluster Hamiltonian of eq 1, in agreement with the magnetometry results. By considering in the model also the excited S = 8 multiplet, as derived in the section from INS experiments (vide infra), split by the same anisotropy constant D/k B = −0.045 K, 37 the calculated curve (red line), lies slightly above the experimental data.…”

Section: ■ Resultsmentioning

confidence: 99%

“…The parameters D / k B = −0.045 K and g = 2 (isotropic) were used, the same previously found by EPR measurements. 37 This kind of experiment and procedure was applied earlier to a single crystal of Mn 12 -PrCl. 40 The calculated magnetization is shown in Figure 3 as solid curves for 1.8 K (black), 5 K (blue), and 10 K (red).…”

Section: Resultsmentioning

confidence: 99%

“…The high-energy feature at (iv) 0.8 meV can be explained as caused by transitions to higher multiples of the S = 8, 9, and 10, in agreement with the previously suggested estimation of ≈ 10 K (≈ 0.86 meV) from EPR measurements. 37 …”

Section: Resultsmentioning

confidence: 99%

“…From the eigenvalues and eigenfunctions, the partition function was calculated, and the magnetization M (θ, T , H ) was predicted, within the Boltzman statistics, at fixed temperature and field modulus, at varying θ. The parameters D / k B = −0.045 K and g = 2 (isotropic) were used, the same previously found by EPR measurements . This kind of experiment and procedure was applied earlier to a single crystal of Mn 12 -PrCl .…”

Section: Resultsmentioning

confidence: 99%

“…Only one of the members of this family, denoted as 5 in ref ( 36 ), carrying R = Me and the largest R′ group (CMe 3 ), shows an overall FM behavior down to the lowest temperature (1.8 K), although it is peculiar, as the magnetization does not saturate at the expected 30 μ B /fu for 10 FM coupled 3/2 spin Cr 3+ ions but to a much lower value, indicating a ground state different from S = 15. Electron paramagnetic resonance (EPR) measurements were performed by Sharmin et al 37 for this member of the family, with applied magnetic field along the axis perpendicular to the average {Cr 10 } ring’s plane. The absorption spectrum indicated a spin S = 9 ground state, whose temperature dependence suggests an excited state at ca.…”

Section: Introductionmentioning

confidence: 99%

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Origin of the Unusual Ground-State Spin S = 9 in a Cr₁₀ Single-Molecule Magnet

et al. 2022

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The molecular wheel [Cr10(OMe)20(O2CCMe3)10], abbreviated {Cr10}, with an unusual intermediate total spin S = 9 and non-negligible cluster anisotropy, D/k B = −0.045(2) K, is a rare case among wheels based on an even number of 3d-metals, which usually present an antiferromagnetic (AF) ground state (S = 0). Herein, we unveil the origin of such a behavior. Angular magnetometry measurements performed on a single crystal confirmed the axial anisotropic behavior of {Cr10}. For powder samples, the temperature dependence of the susceptibility plotted as χT(T) showed an overall ferromagnetic (FM) behavior down to 1.8 K, whereas the magnetization curve M(H) did not saturate at the expected 30 μB/fu for 10 FM coupled 3/2 spin Cr3+ ions, but to a much lower value, corresponding to S = 9. In addition, the X-ray magnetic circular dichroism (XMCD) measured at high magnetic field (170 kOe) and 7.5 K showed the polarization of the cluster moment up to 23 μB/fu. The magnetic results can be rationalized within a model, including the cluster anisotropy, in which the {Cr10} wheel is formed by two semiwheels, each with four Cr3+ spins FM coupled (J FM/k B = 2.0 K), separated by two Cr3+ ions AF coupled asymmetrically (J 23/k B = J 78/k B = −2.0 K; J 34/k B = J 89/k B = −0.25 K). Inelastic neutron scattering and heat capacity allowed us to confirm this model leading to the S = 9 ground state and first excited S = 8. Single-molecule magnet behavior with an activation energy of U/k B = 4.0(5) K in the absence of applied field was observed through ac susceptibility measurements down to 0.1 K. The intriguing magnetic behavior of {Cr10} arises from the detailed asymmetry in the molecule interactions produced by small-angle distortions in the angles of the Cr–O–Cr alkoxy bridges coupling the Cr3+ ions, as demonstrated by ab initio and density functional theory calculations, while the cluster anisotropy can be correlated to the single-ion anisotropies calculated for each Cr3+ ion in the wheel.

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Section: ■ Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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