Magnetic anisotropy in the molecular complex<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">V</mml:mi></mml:mrow><mml:mrow><mml:mn>15</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Konstantinidis, N.; Coffey, D.

doi:10.1103/physrevb.66.174426

Cited by 42 publications

(56 citation statements)

References 39 publications

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“…We set J = −800K, J 2 = −350K, and J 1 = −225K. 20 The second term describes the DMI. We assume the existence of DM vectors {D ij } at the bonds of J.…”

Section: -19mentioning

confidence: 99%

ESR intensity and the Dzyaloshinsky-Moriya interaction of the nanoscale molecular magnet V15

2012

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The intensity of electron spin resonance (ESR) of the nanoscale molecular magnet V 15 is studied. We calculate the temperature dependence of the intensity at temperatures from high to low. In particular, we find that the low-temperature ESR intensity is significantly affected by the Dzyaloshinsky-Moriya interaction. I. INTRODUCTIONThe V 15 molecule has been one of promising nanometer-scale molecular magnets since it was first synthesized. Different experiments on the magnetization process have shown that the magnetization changed adiabatically in a fast sweeping field, and a magnetic plateau appeared in a slow sweeping field due to thermal bath attached to the molecule. are not yet fully understood.In this paper, first we numerically calculate the temperature dependence of the ESR intensity of V 15 using a new numerical method (the double Chebyshev polynomial method) of calculating the Kubo formula. We find that the model Hamiltonian for V 15 including the DMI successfully reproduces the experimental temperature dependence of the ESR intensity.Second we investigate the ESR at very low temperatures. We find that the intensity ratio (the intensity of V 15 divided by that of a spin 1/2) is affected by the DMI at small fields.We propose that experimental observation of the intensity ratio enables us to estimate the DMI in V 15 . Finally, we analyze the ESR at low temperatures using a triangle model whose 2 energy levels model the low-lying levels of V 15 . Figure 1 shows the structure of vanadium ions in V 15 . We consider the following spin II. MODEL AND FORMULATIONHamiltonian for V 15 . 17-19The first term on the right-hand side of Eq. (1) describes the Heisenberg interaction. Coefficients J ij take three values J, J 1 , and J 2 (|J| > |J 2 | > |J 1 |) depending on the bonds on the upper and lower hexagons. Three spins between two hexagons interact with the hexagons by J 1 and J 2 . There is no interaction among these three spins 3 . We set J = −800K, J 2 = −350K, and J 1 = −225K. 20 The second term describes the DMI. We assume the existence of DM vectors {D ij } at the bonds of J. In the third term, H denotes the static magnetic field applied to the molecule. We will ignore other effects such as dipolar fields, hyperfine interactions, and the crystal field, which are considered to be negligibly small.Indeed, the dipolar and hyperfine fields are estimated as 1 mK and 50 mK, respectively 7 .

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“…We set J = −800K, J 2 = −350K, and J 1 = −225K. 20 The second term describes the DMI. We assume the existence of DM vectors {D ij } at the bonds of J.…”

Section: -19mentioning

confidence: 99%

ESR intensity and the Dzyaloshinsky-Moriya interaction of the nanoscale molecular magnet V15

2012

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“…owing to the DM interaction, should broaden the spin state transition. 22 This may explain a large width ∼ 10 T of the magnetization step of NiAz at H crit ∼ 25 T (Fig. 9).…”

Section: Ground State In Strong Magnetic Fieldsmentioning

confidence: 99%

“…Possibly, as suggested by theoretical calculations in Ref. 22, for particular orientations of the DM vector the width of the magnetization step may increase appreciably with increasing H crit . Thus the experimentally available field range limited to 55 T might not be sufficient for the observation of the second strongly smeared out magnetization step.…”

Section: Ground State In Strong Magnetic Fieldsmentioning

confidence: 99%

“…In particular, in the presence of an anisotropic interaction one may expect the occurrence of an anti-crossing energy gap between the S = 0 singlet state and the | −1 state of the S = 1 triplet near the level crossing point at H crit . 22 Experimentally such a gap yields a hysteresis behavior of the static magnetization owing to nonequilibrium processes in the spin system which depends on the sweep rate of the magnetic field ∂H/∂t (see e.g. Ref.…”

Section: Ground State In Strong Magnetic Fieldsmentioning

confidence: 99%

“…Indeed, recent theoretical calculations reveal an important role of the DM term for the microscopic description of the magnetization of paramagnetic molecular clusters. 22 To examine the relevance of the DM interaction to the case of NiAz theoretical modelling beyond the framework of Hamiltonian (1) is highly desirable. In particular, in the presence of an anisotropic interaction one may expect the occurrence of an anti-crossing energy gap between the S = 0 singlet state and the | −1 state of the S = 1 triplet near the level crossing point at H crit .…”

Section: Ground State In Strong Magnetic Fieldsmentioning

confidence: 99%

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Tuning the magnetic ground state of a tetranuclear nickel(II) molecular complex by high magnetic fields

et al. 2006

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Electron spin resonance and magnetization data in magnetic fields up to 55 T of a novel multicenter paramagnetic molecular complex [L2Ni4(N3)(O2C Ada)4](Cl O4) are reported. In this compound, four Ni centers each having a spin S = 1 are coupled in a single molecule via bridging ligands (including a µ4-azide) which provide paths for magnetic exchange. Analysis of the frequency and temperature dependence of the ESR signals yields the relevant parameters of the spin Hamiltonian, in particular the single ion anisotropy gap and the g factor, which enables the calculation of the complex energy spectrum of the spin states in a magnetic field. The experimental results give compelling evidence for tuning the ground state of the molecule by magnetic field from a nonmagnetic state at small fields to a magnetic one in strong fields owing to the spin level crossing at a field of ∼ 25 T.

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Single‐Molecule Magnets Under Pressure

Bircher

Chaboussant

Dobe

et al. 2006

Adv Funct Materials

149

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We feature our recent work in the field of single‐molecule magnets (SMMs) using inelastic neutron scattering (INS). The term “pressure” in the title has a triple meaning. First, there is the expectation from research‐funding agencies and the public to make some significant steps towards applications. Second, the synthesis of new compounds and the applications of physical techniques for their understanding are being pushed to their limits. And third, by applying hydrostatic pressure, valuable insight into the mechanisms behind the SMM phenomena can be gained. Examples from our research have been taken to illustrate these points. After a brief introduction to the technique, the strength of INS for the accurate determination of exchange and anisotropy interactions in SMMs is highlighted. We hope to demonstrate that, by pushing INS measurements to their limits, i.e., using the best available neutron sources and instrumentation, combined with high quality samples, new insights into the relevant physical processes in SMMs can be gained.

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Magnetic anisotropy in the molecular complexV15

Cited by 42 publications

References 39 publications

ESR intensity and the Dzyaloshinsky-Moriya interaction of the nanoscale molecular magnet V15

ESR intensity and the Dzyaloshinsky-Moriya interaction of the nanoscale molecular magnet V15

Tuning the magnetic ground state of a tetranuclear nickel(II) molecular complex by high magnetic fields

Single‐Molecule Magnets Under Pressure

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