A Record Anisotropy Barrier for a Single-Molecule Magnet

Milios, Constantinos J.; Vinslava, Alina; Wernsdorfer, Wolfgang; Moggach, Stephen A.; Parsons, Simon; Perlepes, Spyros P.; Christou, George; Brechin, Euan K.

doi:10.1021/ja068961m

Cited by 727 publications

(551 citation statements)

References 9 publications

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“…3 For {Mn 12 } family of complexes the theoretical barrier height is estimated to be 60 K. Recently many lanthanide complexes reported to have higher barrier height, 4 in particular a {Dy 5 (III)} cluster with a barrier of 540 K. 5 Moreover monomeric Tb(III) complex with phthalocyaninate ligands reported to have a barrier height of about 800 K, 6 the largest known for such class of molecules. However, in most lanthanide based SMMs the quantum tunneling of magnetization is very fast leading the very small coercitivity in the hysteresis loop, a remarkable exception being the lanthanide dimers bridged by the N 3 -radical 7,8 Regarding clusters of transition metal complexes, a breakthrough has been achieved with the discovery of a family of {Mn 6 } complexes [Mn(III) 6 O 2 (sao) 6 (O 2 C-th) 2 L 4-6 ], 9 where HO 2 C-ph=3-phenil carboxylic acid, L = EtOH, H 2 O, possessing a barrier height of ca. 90 K. This is the highest reported for any transition metal SMM so far.…”

Section: Introductionmentioning

confidence: 99%

Computational Studies on SAMs of {Mn₆} SMMs on Au(111): Do Properties Change upon Grafting?

et al. 2013

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Single molecule magnets (SMM) adsorbed on surfaces as magnetic building blocks represent a hot topic of research in the area of molecular magnetism. Indeed, the understanding the properties of molecules on surface is extremely challenging as atomistic structures are not readily available. In this regard, theoretical studies as reliable tool to reproduce and predict the structure and the magnetic ground state of SMMs in the bulk phase and adsorbed on a surface, should be considered very appealing. In this framework, we report a periodic density functional (DF) study on two Mn-6 SMM complexes of general formula Mn(III)(6)O-2(R-sao)(6)(O2C-th)(2)L], where HO2C-th=3-thiophene carboxylic acid, saoH(2) = salicylaldoxime, R = H and L = (EtOH)(4) (1) or R = Et and L = (EtOH)(4)(H2O)(2) (2), performed to ascertain the structure of their self-assembled monolayers (SAM) on the Au(111) surface. Their magnetic properties in vacuum and in the adsorbed state have also been computed and our results clearly demonstrate that the grafting process is expected to not be a smooth one as it alters their bulk structure and, consequently, their magnetic properties. ACS Paragon Plus EnvironmentThe Journal of Physical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 (1) or R = Et and L = (EtOH) 4 (H2O) 2 (2) , performed to ascertain the structure of their selfassembled monolayers (SAM) on the Au(111) surface. Their magnetic properties in vacuum and in the adsorbed state have also been computed and our results clearly demonstrate that the grafting process is expected to not be a smooth one as it alters their bulk structure and, consequently, their magnetic properties.

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Section: Introductionmentioning

confidence: 99%

Computational Studies on SAMs of {Mn₆} SMMs on Au(111): Do Properties Change upon Grafting?

et al. 2013

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“…6,7 A previous suggestion 3 that the addition of active radicals with unpaired electrons could result in higher blocking temperatures is consistent with recent reports for {[L 2 (thf)Ln] 2 (µ−η 2 :η 2 -N 2 )} -, 1, (L = N(SiMe 3 ) 2 , thf = tetrahydrofuran), which display hysteresis to 8.3 K, and 14 K for Ln = Dy and Tb (1-Dy and 1-Tb), respectively. 8,9 In contrast, the best transition metal SMM possesses hysteresis to 4.5 K. 10 Single molecule magnetic behavior arises from an energy barrier, U eff , (usually due to zero field splitting in transition metal clusters and to ligand field anisotropy in lanthanide and actinide complexes) that inhibits magnetization reversal in an applied field and "freezes" the magnetic state of the system. The magnetic relaxation time of an SMM, τ, is related to the energy barrier by an Arrhenius relationship, τ = τ 0 exp(U eff /k B T).…”

Section: Introductionmentioning

confidence: 99%

Application of the Hubbard Model to Cp*₂Yb(bipy), a Model System for Strong Exchange Coupling in Lanthanide Systems

2012

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Exchange coupling is quantified in lanthanide (Ln) single molecule magnets (SMMs) containing a bridging N 2 3-radical ligand and between [Cp* 2 Yb] + and bipy -in Cp* 2 Yb(bipy) where Cp* is pentamethylcyclopentadienyl and bipy is 2,2'-bipyridyl. In the case of these lanthanide SMMs, the magnitude of exchange coupling between the Ln ion and the bridging N 2 3-, 2J, is very similar to the barrier to magnetic relaxation, U eff . A molecular version of the Hubbard model is applied to systems in which unpaired electrons on magnetic metal ions have direct overlap with unpaired electrons residing on ligands. The Hubbard model explicitly addresses electron correlation, which is essential for understanding the magnetic behavior of these complexes. This model is applied quantitatively to Cp* 2 Yb(bipy) to explain its very strong exchange coupling, 2J = -0.11 eV (-920 cm -1 ). The model is also used to explain the presence of strong exchange coupling in Ln SMMs in which the lanthanide spins are coupled via bridging N 2 3-radical ligands. The results suggest that increasing the magnetic coupling in lanthanide clusters could lead to an increase in the blocking temperatures of exchange-coupled lanthanide SMMs suggesting routes to the rational design of future lanthanide SMMs.

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“…Beste hainbat ikerketa talde ere aritu izan dira mota honetako koordinazio konposatuak ikertzen [5] eta, orokorrean, ondorio berera iritsi dira. Mn6 [6] eta Fe19 [7] sistemetan D = -0,43 cm Ishikawaren taldeak beste pauso garrantzitsu bat eman zuen. Lur-arraro edo lantanidoetan oinarritutako lehen iman molekularra deskribatu zuten (5. irudia) [9].…”

Section: Anisotropia Faktore Kritikounclassified

Iman Molekularrak: Informazio unitate txikienaren bila

Zabala-Lekuona

2019

EKAIA

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Hitz gakoak: iman molekularrak, trantsizio metalak, lantanidoak, magnetismoa.Abstract: Nowadays, storing the highest possible amount of information in size reduced devices is one of important concerns of society. Even though this kind of technology is quite developed, the discovery of the Mn12-ac coordination compound in 1993 was considered a huge step. This is because Single Molecule Magnets (SMMs) represent the smallest information units. Therefore, new devices based on this kind of materials would enhance information storage capacity. In the present work, the most important and representative discoveries since 1993 have been summarized.

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A Record Anisotropy Barrier for a Single-Molecule Magnet

Abstract: Structural distortion in a [Mn6] complex switches the magnetic exchange from antiferro- to ferromagnetic, resulting in a single-molecule magnet with a record anisotropy barrier.

Cited by 727 publications

References 9 publications

Computational Studies on SAMs of {Mn₆} SMMs on Au(111): Do Properties Change upon Grafting?

Computational Studies on SAMs of {Mn₆} SMMs on Au(111): Do Properties Change upon Grafting?

Application of the Hubbard Model to Cp*₂Yb(bipy), a Model System for Strong Exchange Coupling in Lanthanide Systems

Iman Molekularrak: Informazio unitate txikienaren bila

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A Record Anisotropy Barrier for a Single-Molecule Magnet

Abstract: Structural distortion in a [Mn6] complex switches the magnetic exchange from antiferro- to ferromagnetic, resulting in a single-molecule magnet with a record anisotropy barrier.

Cited by 727 publications

References 9 publications

Computational Studies on SAMs of {Mn6} SMMs on Au(111): Do Properties Change upon Grafting?

Computational Studies on SAMs of {Mn6} SMMs on Au(111): Do Properties Change upon Grafting?

Application of the Hubbard Model to Cp*2Yb(bipy), a Model System for Strong Exchange Coupling in Lanthanide Systems

Iman Molekularrak: Informazio unitate txikienaren bila

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Computational Studies on SAMs of {Mn₆} SMMs on Au(111): Do Properties Change upon Grafting?

Computational Studies on SAMs of {Mn₆} SMMs on Au(111): Do Properties Change upon Grafting?

Application of the Hubbard Model to Cp*₂Yb(bipy), a Model System for Strong Exchange Coupling in Lanthanide Systems