High-temperature magnetic blocking and magneto-structural correlations in a series of dysprosium(<scp>iii</scp>) metallocenium single-molecule magnets

McClain, K. Randall; Gould, Colin A.; Chakarawet, Khetpakorn; Teat, Simon J.; Groshens, Thomas J.; Long, Jeffrey R.; Harvey, Benjamin G.

doi:10.1039/c8sc03907k

Cited by 444 publications

(284 citation statements)

References 65 publications

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“…Single‐molecule magnets (SMMs) are molecules that show slow relaxation of magnetisation, and because of this behaviour, they have long been proposed as the ultimate high‐density magnetic storage media . Until recently, this had seemed to be a slightly fanciful proposition, but SMMs based on lanthanide ions, particularly dysprosium(III), have shown barriers for thermal relaxation of magnetisation ( U eff ) approaching 1500 cm −1 , and a magnetic hysteresis has been seen at 60 K and even higher temperatures . These breakthroughs have changed the field of SMMs and yet there is still a limited understanding of the physics that underpins the relaxation of magnetisation in these species.…”

Section: Introductionmentioning

confidence: 99%

“…In polymetallic 3 d‐block SMMs, the value of U eff is typically <100 cm −1 , but the Orbach process usually controls relaxation at almost all temperatures . For lanthanide SMMs, and in some pseudo‐linear 3 d‐metal compounds, U eff is much larger, and the Raman term becomes important at lower temperatures . Recently, it has been shown that there is a correlation between the temperature at which magnetisation is retained, often called the blocking temperature, and the relaxation time at the point where the Raman process takes over from the Orbach process …”

Section: Introductionmentioning

confidence: 99%

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A Study of Magnetic Relaxation in Dysprosium(III) Single‐Molecule Magnets

Ding

Han

Zhai

et al. 2020

Chemistry A European J

128

118

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Although the development of single‐molecule magnets (SMMs) is rapid, there are only two families of high energy barrier (Ueff) dysprosium(III) SMMs known so far: the cyclopentadienyl (Cp) family with a sandwich structure and the pentagonal‐bipyramidal (PB) family with D5h symmetry. These high‐barrier SMMs, which usually possess Ueff>500 cm−1 allow the separate study of the four magnetic relaxation paths, namely, direct, quantum tunnelling, Raman and Orbach processes, in detail. Whereas the first family is chemically more challenging to modify the Cp rings, it is shown herein that the latter family, with the common formulae [DyX1X2(Leq)5]+, such as X1/X2=−OCMe3, −OSiMe3, −OPh, Cl− or Br−; Leq=THF/pyridine/4‐methylpyridine, can be readily fine‐tuned with a range of axial and equatorial ligands by simple substitution reactions. This allows unambiguous confirmation that the Ueff mainly depends on the identity of X1 and X2, rather than on Leq. More importantly, the fitted parameters are barrier dependent. If X1 is an O donor and X2 is a halide, 500

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Study of Magnetic Relaxation in Dysprosium(III) Single‐Molecule Magnets

Ding

Han

Zhai

et al. 2020

Chemistry A European J

128

118

View full text Add to dashboard Cite

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“…Recently, it has been shown that the hysteretic behavior can be reinforced by minimizing underbarrier relaxation pathways and engineering the coupling between the vibrational modes of the ligands and the magnetic states of the core [13][14][15]. Combining these approaches has enabled hysteresis up to unprecedented temperatures of 72 [16] and 80 K [17].…”

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confidence: 99%

Unconventional Spin Relaxation Involving Localized Vibrational Modes in Ho Single-Atom Magnets

et al. 2020

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We investigate the spin relaxation of Ho single atom magnets on MgO=Agð100Þ as a function of temperature and magnetic field. We find that the spin relaxation is thermally activated at low field, while it remains larger than 1000 s up to 30 K and 8 T. This behavior contrasts with that of single molecule magnets and bulk paramagnetic impurities, which relax faster at high field. Combining our results with density functional theory, we rationalize this unconventional behavior by showing that local vibrations activate a twophonon Raman process with a relaxation rate that peaks near zero field and is suppressed at high field. Our work shows the importance of these excitations in the relaxation of axially coordinated magnetic atoms.

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“…The control of the magnetic anisotropy is driven by the nature and the position of the ligands around the metal center. Thus, recently, the use of cyclopentadienyl-based ligands has allowed for the design of mononuclear lanthanide SMMs with a high blocking temperature [20][21][22][23]. These two research fields highlight the important role of the organic ligands associated to the lanthanide ion.…”

Section: Introductionmentioning

confidence: 99%

Dysprosium Single-Molecule Magnets Involving 1,10-Phenantroline-5,6-dione Ligand

et al. 2020

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The two mononuclear complexes of the formula [Dy(tta) 3 (L)] (1) and [Dy(hfac) 3 (L)] (2) (where tta -= 2-thenoytrifluoroacetylacetonate and hfac -= 1,1,1,5,5,5-hexafluoroacetylacetonate) were obtained from the coordination reaction of the Dy(tta) 3 ·2H 2 O or Dy(hfac) 3 ·2H 2 O units with the 1,10-phenantroline-5,6-dione ligand (L). Their structures have been determined by X-ray diffraction studies on single crystals, and they revealed a supramolecular assembly of tetramers through σ-π interactions. Both complexes displayed a Single-Molecule Magnet (SMM) behavior without an external applied magnetic field. Magnetic relaxation happened through Orbach, Raman and Quantum Tunneling of the Magnetization (QTM). Wavefunction theory calculations were realized to rationalize the magnetic properties.

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High-temperature magnetic blocking and magneto-structural correlations in a series of dysprosium(iii) metallocenium single-molecule magnets

Abstract: Subtle changes in ligand substitution result in substantial changes in molecular structure and magnetic properties in a series of dysprosium(iii) metallocenium salts.

Cited by 444 publications

References 65 publications

A Study of Magnetic Relaxation in Dysprosium(III) Single‐Molecule Magnets

A Study of Magnetic Relaxation in Dysprosium(III) Single‐Molecule Magnets

Unconventional Spin Relaxation Involving Localized Vibrational Modes in Ho Single-Atom Magnets

Dysprosium Single-Molecule Magnets Involving 1,10-Phenantroline-5,6-dione Ligand

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