Estimation of higher-order magnetic spin interactions of Fe(III) and Gd(III) ions doped in α-alumina powder with multifrequency EPR

Priem, A.; Bentum, P.J.M. van; Hagen, Wilfred R.; Reijerse, Eduard J.

doi:10.1007/bf03162427

Cited by 16 publications

(17 citation statements)

References 14 publications

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“…For instance, an anisotropy of |D| = 0.24 K, which is comparable with that evaluated for CuFeO 2 in our study, was reported for Fe 3+ ions doped in Al 2 O 3 . 40 The other origin is a magnetic dipole-dipole interaction between Fe 3+ spins. The 4-sublattice structure at zero field has no threefold symmetry around the c axis.…”

Section: Discussion and Summarymentioning

confidence: 99%

Multifrequency ESR measurements of the triangular lattice antiferromagnet CuFeO2in high magnetic fields

et al. 2011

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We have performed multifrequency electron spin resonance (ESR) measurements of the triangular lattice antiferromagnet CuFeO 2 , which shows peculiar magnetic ordering and field-induced phase transitions, in high magnetic fields of up to 53 T. Our analysis of the ESR modes and energy dispersion explains the overall behaviors of magnetic excitations in the collinear 4-sublattice phase of this material. We show changes of the exchange interactions due to the lattice distortion of CuFeO 2 , suggesting strong spin-lattice coupling in this material. In addition, we evaluate the precise value of the magnetic anisotropy in CuFeO 2 from the ESR and magnetization measurements. The presence of relatively large second-and third-nearest-neighbor intralayer exchange interactions is also indicated. We discuss that the strong spin-lattice coupling, the large farther neighbor exchange interactions, and the finite axial anisotropy are important to understand the magnetic phase transitions of CuFeO 2 .

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Section: Discussion and Summarymentioning

confidence: 99%

Multifrequency ESR measurements of the triangular lattice antiferromagnet CuFeO2in high magnetic fields

et al. 2011

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“…(1 , which we must consider in the case of symmetry fields lower than 31 In this work, however, significant shift caused by the odd terms was not seen in the observed X-band spectrum.…”

Section: Discussionmentioning

confidence: 63%

“…These parameters may be determined by careful analysis of extra lines observed in the X-band spectrum. Recently, estimation of the value from extra lines was discussed for S -state ions in trigonal symmetry by Priem et al In this work, however, significant shift caused by the odd terms was not seen in the observed X-band spectrum. General Expression for Resonance Field of M S = 1/2 ↔ − 1/2 Transition Arising from S = 7/2 Spin System under Second-Order Approximation.…”

mentioning

confidence: 57%

Importance of Fourth-Order Zero-Field Splitting Terms in Random-Orientation EPR Spectra of Eu(II)-Doped Strontium Aluminate

et al. 2003

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This work discusses an issue caused by omitting the fourth-order zero-field splitting (ZFS) terms in the analysis of random-orientation EPR spectra. Eu(II)-doped strontium aluminates were employed as a model system of the S-state lanthanoid ions, which have relatively large second-rank ZFS components, comparable to the conventional X-band microwave energy. The initial estimation of second-and fourth-rank ZFS components was acquired uniquely from the W-band spectrum based on a perturbation treatment of the spin Hamiltonian, and they were refined by a hybrid-eigenfield simulation approach. A parallel simulation of the X-and W-band spectra with the refined parameters reasonably reproduced both the observed spectra. The reliability of the parameters was also verified by reproducing the off-principal-axis extra lines arising from the M S ) 1/2 T -1/2 transition observed in the W-band spectrum. By comparison with an analysis based on the spin Hamiltonian omitting the fourth-order terms, it was concluded that omitting these terms results in an erroneous determination of the rhombic parameter (E) of the second-rank ZFS tensor. The obtained reliable secondrank ZFS tensors enabled us to invoke the superposition model, determining their principal-axis orientation. This is the first report of such relative orientation determined for Eu(II)-doped strontium aluminates.

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“…The Q-band spectra were well fit using the same parameters as the X-band data. At both frequencies we label the g values with prime symbols indicating that they are only effective values, which are skewed from the usual high-spin Fe 3+ values (g ∼ 2.002-2.009), 22,[47][48][49] due to large zfs, a result that has been seen in many high-spin Fe 3+ systems. 22,[47][48][49] For example, the report of large g-values has been seen in biological systems with high spin ferric ions like the heme proteins [47][48][49][50][51] and in other Fe 3+ porphyrinates where the effective g values have been shown to range from ∼7.7 to 1.8.…”

Section: Magnetic Behaviormentioning

confidence: 99%

“…At both frequencies we label the g values with prime symbols indicating that they are only effective values, which are skewed from the usual high-spin Fe 3+ values (g ∼ 2.002-2.009), 22,[47][48][49] due to large zfs, a result that has been seen in many high-spin Fe 3+ systems. 22,[47][48][49] For example, the report of large g-values has been seen in biological systems with high spin ferric ions like the heme proteins [47][48][49][50][51] and in other Fe 3+ porphyrinates where the effective g values have been shown to range from ∼7.7 to 1.8. 39 The EPR data, combined with magnetic susceptibility, unambiguously show that the iron center in these compounds exists as a high-spin ferric ion, with a large axial zfs and non vanishing rhombic zfs.…”

Section: Magnetic Behaviormentioning

confidence: 99%

Six-coordinate ferric porphyrins containing bidentate N-t-butyl-N-nitrosohydroxylaminato ligands: structure, magnetism, IR spectroelectrochemisty, and reactivity

Christian

Dalal

et al. 2015

Dalton Trans.

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NONOates (diazeniumdiolates) containing the [X{N2O2}](-) functional group are frequently employed as nitric oxide (NO) donors in biology, and some NONOates have been shown to bind to metalloenzymes. We report the preparation, crystal structures, detailed magnetic behavior, redox properties, and reactivities of the first isolable alkyl C-NONOate complexes of heme models, namely (OEP)Fe(η(2)-ON(t-Bu)NO) (1) and (TPP)Fe(η(2)-ON(t-Bu)NO) (2) (OEP = octaethylporphyrinato dianion, TPP = tetraphenylporphyrinato dianion). The compounds display the unusual NONOate O,O-bidentate binding mode for porphyrins, resulting in significant apical Fe displacements (+0.60 Å for 1, and +0.69 Å for 2) towards the axial ligands. Magnetic susceptibility and magnetization measurements made from 1.8-300 K at magnetic fields from 0.02 to 5 T, yielded magnetic moments of 5.976 and 5.974 Bohr magnetons for 1 and 2, respectively, clearly identifying them as high-spin (S = 5/2) ferric compounds. Variable-frequency (9.4 GHz and 34.5 GHz) EPR measurements, coupled with computer simulations, confirmed the magnetization results and yielded more precise values for the spin Hamiltonian parameters: g(avg) = 2.00 ± 0.03, |D| = 3.89 ± 0.09 cm(-1), and E/D = 0.07 ± 0.01 for both compounds, where D and E are the axial and rhombic zero-field splittings. IR spectroelectrochemistry studies reveal that the first oxidations of these compounds occur at the porphyrin macrocycles and not at the Fe-NONOate moieties. Reactions of 1 and 2 with a histidine mimic (1-methylimidazole) generate RNO and NO, both of which may bind to the metal center if sterics allow, as shown by a comparative study with the Cupferron complex (T(p-OMe)PP)Fe(η(2)-ON(Ph)NO). Protonation of 1 and 2 yields N2O as a gaseous product, presumably from the initial generation of HNO that dimerizes to the observed N2O product.

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Estimation of higher-order magnetic spin interactions of Fe(III) and Gd(III) ions doped in α-alumina powder with multifrequency EPR

Cited by 16 publications

References 14 publications

Multifrequency ESR measurements of the triangular lattice antiferromagnet CuFeO2in high magnetic fields

Multifrequency ESR measurements of the triangular lattice antiferromagnet CuFeO2in high magnetic fields

Importance of Fourth-Order Zero-Field Splitting Terms in Random-Orientation EPR Spectra of Eu(II)-Doped Strontium Aluminate

Six-coordinate ferric porphyrins containing bidentate N-t-butyl-N-nitrosohydroxylaminato ligands: structure, magnetism, IR spectroelectrochemisty, and reactivity

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