Multi-frequency EPR studies of a mononuclear holmium single-molecule magnet based on the polyoxometalate [HoIII(W5O18)2]9−

Ghosh, Sanhita; Datta, Saiti; Friend, Lisa; Cardona‐Serra, Salvador; Gaita‐Ariño, Alejandro; Coronado, Eugenio; Hill, Stephen

doi:10.1039/c2dt31674a

Cited by 96 publications

(84 citation statements)

References 34 publications

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“…This, indeed, requires the presence of a strong uniaxial magnetic anisotropy and, hence, a good knowledge of the magneto-structural relationships at the molecular level [1,2] Side by side with numerous theoretical studies based on quantum calculations [3][4][5], such knowledge has been greatly improved by the use of experimental methods, such as electron paramagnetic resonance spectroscopy (EPR) [6] or, more recently, by angular-resolved or torque magnetometry [7,8]. The main difficulty with these methods is to access the local magnetic anisotropy even when performed on single crystals.…”

Section: Introductionmentioning

confidence: 99%

Mapping the Magnetic Anisotropy inside a Ni4 Cubane Spin Cluster Using Polarized Neutron Diffraction

et al. 2017

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Abstract:In this publication, we report on the study of the magnetic anisotropy of the cubane type tetranuclear cluster of Ni(II), [Ni 4 (L) 4 (MeOH) 4 ] (H 2 L = salicylidene-2-ethanolamine; MeOH = methanol), by the means of angular-resolved magnetometry and polarized neutron diffraction (PND). We show that better than other usual characterization techniques-such as electron paramagnetic resonance spectroscopy (EPR) or SQUID magnetometry-only PND enables the full determination of the local magnetic susceptibility tensor of the tetranuclear cluster and those of the individual Ni(II) ions and the antiferromagnetic pairs they form. This allows highlighting that, among the two antiferromagnetic pairs in the cluster, one has a stronger easy-axis type anisotropy. This distinctive feature can only be revealed by PND measurements, stressing the remarkable insights that they can bring to the understanding of the magnetic properties of transition metals clusters.

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Section: Introductionmentioning

confidence: 99%

Mapping the Magnetic Anisotropy inside a Ni4 Cubane Spin Cluster Using Polarized Neutron Diffraction

et al. 2017

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“…In contrast, the attempts of using lanthanide-based SIMs as spin qubits have just begun [8,9,68,69]. Examples we will discuss include some lanthanide polyoxometalates [70][71][72][73], the famous TbPc 2 [39,40,74,75] and one Yb complex [76], see also Table 4. …”

Section: Single-ion Magnetic Molecules With Single 4f Spinsmentioning

confidence: 99%

“…Another single-lanthanide polyoxometalate for spin qubit is the complex [Ho(W 5 O 18 P) 2 ] 9− (26) [72,73], an analogy of GdW 10 with a different lanthanide center. The Ho(III) ion is encapsulated between two W 5 O 18 POM units that provide a square-antiprismatic coordination geometry with D 4d symmetry (Figure 13a).…”

Section: Single-lanthanide Polyoxometalates As Spin Qubitsmentioning

confidence: 99%

“…By high-frequency and X-band EPR measurements, the hyperfine-split m J = ±4 ground states can be observed (Figure 13b). The tunneling gap is about 9 GHz, which make 26 suitable for spin qubits [72]. The dilution study of 26 was carried out on Na 9 [Ho x Y (1-x) (W 5 O 18 ) 2 ]·nH 2 O, where x ranges from 0.001 to 0.25 [73].…”

Section: Single-lanthanide Polyoxometalates As Spin Qubitsmentioning

confidence: 99%

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The Rise of Single-Ion Magnets as Spin Qubits

2016

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Recent studies revealed that magnetic molecules with single spin centers showed exciting phenomena related to quantum information processing, such as long quantum coherence times and Rabi oscillations. In this review, we go over these phenomena according to the essential metal ions, from which we can see the development of single-ion magnets as spin qubits is booming, especially quantum coherence times have been significantly enhanced from nanoseconds to hundreds of microseconds in a short period. Hence, the correlations between the molecular structures and quantum coherence are becoming clearer. In this regard, some chemical approaches to designing better spin qubits have been discussed.

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“…Molecular nanomagnets are particularly attractive as spin qubits [4][5][6][7][8][9][10][11][12] because many of their properties can be chemically engineered. Single-molecule magnets (SMMs) are anisotropic molecular magnets, typically with large total spin, for which the spin is impelled to point along a preferred axis, the "easy" axis [13].…”

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confidence: 99%

Observation of Tunneling-Assisted Highly Forbidden Single-Photon Transitions in a Ni4 Single-Molecule Magnet

et al. 2016

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Forbidden transitions between energy levels typically involve violation of selection rules imposed by symmetry and/or conservation laws. A nanomagnet tunneling between up and down states violates angular momentum conservation because of broken rotational symmetry. Here we report observations of highly forbidden transitions between spin states in a Ni4 single-molecule magnet in which a single photon can induce the spin to change by several timesh, nearly reversing the direction of the spin. These observations are understood as tunnelingassisted transitions that lift the standard ∆m = ±1 selection rule for single-photon transitions. These transitions are observed at low applied fields, where tunneling is dominated by the molecule's intrinsic anisotropy and the field acts as a perturbation. Such transitions can be exploited to create macroscopic superposition states that are not typically accessible through single-photon ∆m = ±1 transitions.There has been much recent attention to using spin systems as potential qubits [1][2][3][4]. Molecular nanomagnets are particularly attractive as spin qubits [4][5][6][7][8][9][10][11][12] because many of their properties can be chemically engineered. Single-molecule magnets (SMMs) are anisotropic molecular magnets, typically with large total spin, for which the spin is impelled to point along a preferred axis, the "easy" axis [13]. They exhibit remarkable quantum dynamics including tunneling between different orientations [14] and quantum-phase interference [15]. Here we present evidence of highly forbidden transitions in the Ni 4 SMM where the transitions are enabled by tunneling, which lifts the requirement of spin angular momentum conservation. We observe transitions in which the absorption of a single photon permits a near reversal of the molecule's macrospin, grossly violating the standard ∆m = ±1 selection rule. The quantum states that can be generated through these forbidden transitions are non-classical, having a substantial "macroscopicity" by a standard measure. Our results imply that the forbidden transitions observed in this system (and similar molecules with strong anisotropy) can be exploited to create highly nonclassical states with single-photon transitions.From a quantum coherence perspective, forbidden transitions have some distinct advantages: Since the matrix elements for these transitions are small, they tend to have long lifetimes. In addition, they can be less susceptible to magnetic-field fluctuations under certain circumstances, potentially leading to longer coherence times [3,12,16]. Forbidden transitions have been seen in SMMs with very strong tunneling produced by strongly broken symmetry [11,12,17]. In contrast, in our experiments the transitions are dominated by a modest intrinsic anisotropy with an applied field acting as a perturbation.We studied the S = 4 complex [Ni(hmp)(dmb)Cl] 4 (hereafter Ni 4 ), shown in the inset of Fig. 1. The molecule's large ligands isolate the magnetic centers within a crystal from each other [18]. In addition, there a...

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Multi-frequency EPR studies of a mononuclear holmium single-molecule magnet based on the polyoxometalate [HoIII(W5O18)2]9−

Cited by 96 publications

References 34 publications

Mapping the Magnetic Anisotropy inside a Ni4 Cubane Spin Cluster Using Polarized Neutron Diffraction

Mapping the Magnetic Anisotropy inside a Ni4 Cubane Spin Cluster Using Polarized Neutron Diffraction

The Rise of Single-Ion Magnets as Spin Qubits

Observation of Tunneling-Assisted Highly Forbidden Single-Photon Transitions in a Ni4 Single-Molecule Magnet

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