scholarly journals Trigonal antiprismatic Co(ii) single molecule magnets with large uniaxial anisotropies: importance of Raman and tunneling mechanisms

2016 ◽  
Vol 7 (10) ◽  
pp. 6519-6527 ◽  
Author(s):  
Yuan-Zhu Zhang ◽  
Silvia Gómez-Coca ◽  
Andrew J. Brown ◽  
Mohamed R. Saber ◽  
Xuan Zhang ◽  
...  
Keyword(s):  
Relaxation Process ◽  
Single Molecule ◽  
Single Molecule Magnets

A trigonal antiprismatic Co(ii) molecule exhibits counterion-dependent relaxation of the magnetization due to the importance of the Raman relaxation process.

Dramatic impact of auxiliary ligands on the two-step magnetic relaxation process in Dy4(iii) single-molecule magnets

2019 ◽  
Vol 48 (17) ◽  
pp. 5793-5799 ◽  
Author(s):  
Kun Zhang ◽  
Gao-Peng Li ◽  
Cheng Zhang ◽  
Yao-Yu Wang
Keyword(s):  
Relaxation Process ◽  
Single Molecule ◽  
Magnetic Relaxation ◽  
Relaxation Processes ◽  
Single Molecule Magnets ◽  
Coordination Sites

Two-step relaxation processes are modulated in two Dy(iii)4 SMMs through modifying the auxiliary ligands on the changeable coordination sites.

The origin of the second relaxation process in the [Mn12O12(O2CR)16(H2O)4] single-molecule magnets: ‘Jahn–Teller isomerism’ in the [Mn12O12] core

1999 ◽  
pp. 1973-1974 ◽  
Author(s):  
Ziming Sun ◽  
Daniel Ruiz ◽  
David N. Hendrickson ◽  
Neil R. Dilley ◽  
M. Brian Maple ◽  
...  
Keyword(s):  
Relaxation Process ◽  
Single Molecule ◽  
Single Molecule Magnets ◽  
Jahn Teller

Counter anions influence the relaxation dynamics of phenoxy-bridged Dy2 single molecule magnets

2020 ◽  
Vol 49 (35) ◽  
pp. 12372-12379 ◽  
Author(s):  
Shuting Liu ◽  
Jingjing Lu ◽  
Xiao-Lei Li ◽  
Zhenhua Zhu ◽  
Jinkui Tang
Keyword(s):  
Relaxation Process ◽  
Single Molecule ◽  
Relaxation Dynamics ◽  
Counter Anion ◽  
Dynamic Relaxation ◽  
Single Molecule Magnets

Structural and magnetic investigations into four dinuclear dysprosium complexes reveal that the counter anion influences the dynamic relaxation process in these complexes.

Evolution from a single relaxation process to two-step relaxation processes of Dy2 single-molecule magnets via the modulations of the terminal solvent ligands

2021 ◽  
Vol 50 (1) ◽  
pp. 217-228
Author(s):  
Dawei Li ◽  
Man-Man Ding ◽  
Yuan Huang ◽  
David Felipe Tello Yepes ◽  
Haiyan Li ◽  
...  
Keyword(s):  
Relaxation Process ◽  
Single Molecule ◽  
Relaxation Processes ◽  
Single Molecule Magnets

Three Dy2 SMMs were synthesized and characterized. The target of evolution from a single relaxation process to two-step relaxation processes was achieved by adjusting the sizes of the terminal solvent ligands.

Seeking Magneto-Structural Correlations in Easily Tailored Pentagonal Bipyramid Dy(III) Single-Ion Magnets

2019 ◽  
Author(s):  
Guo-Zhang Huang ◽  
Ze-Yu Ruan ◽  
Jie-Yu Zheng ◽  
Yan-Cong Chen ◽  
Si-Guo Wu ◽  
...  
Keyword(s):  
Single Molecule ◽  
Structural Engineering ◽  
Magnetic Hysteresis ◽  
Sweep Rate ◽  
Coordination Bond ◽  
Pentagonal Bipyramid ◽  
Single Molecule Magnets ◽  
Crystal Field Theory ◽  
Bond Angles ◽  
Axial Coordination

<p><a></a>Controlling molecular magnetic anisotropy via structural engineering is delicate and fascinating, especially for single-molecule magnets (SMMs). Herein a family of dysprosium single-ion magnets (SIMs) sitting in pentagonal bipyramid geometry have been synthesized with the variable-size terminal ligands and counter anions, through which the subtle coordination geometry of Dy(III) can be finely tuned based on the size effect. The effective energy barrier (Ueff) successfully increases from 439 K to 632 K and the magnetic hysteresis temperature (under a 200 Oe/s sweep rate) raises from 11 K to 24 K. Based on the crystal-field theory, a semi-quantitative magneto-structural correlation deducing experimentally for the first time is revealed that the Ueff is linearly proportional to the structural-related value S2<sup>0</sup> corresponding to the axial coordination bond lengths and the bond angles. Through the evaluation of the remanent magnetization from hysteresis, quantum tunneling of magnetization (QTM) is found to exhibit negative correlation with the structural-related value S<sub>tun</sub> corresponding to the axial coordination bond angles.<br></p>

Correlating Blocking Temperatures in Single Molecule Magnets with Raman Relaxation

2018 ◽  
Author(s):  
Marcus J. Giansiracusa ◽  
Andreas Kostopoulos ◽  
George F. S. Whitehead ◽  
David Collison ◽  
Floriana Tuna ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Single Molecule ◽  
Energy Barrier ◽  
Thermal Relaxation ◽  
Relaxation Mechanism ◽  
Blocking Temperature ◽  
Single Molecule Magnets ◽  
Single Molecule Magnet ◽  
Key Parameter

We report a six coordinate DyIII single-molecule magnet<br>(SMM) with an energy barrier of 1110 K for thermal relaxation of<br>magnetization. The sample shows no retention of magnetization<br>even at 2 K and this led us to find a good correlation between the<br>blocking temperature and the Raman relaxation regime for SMMs.<br>The key parameter is the relaxation time (𝜏<sub>switch</sub>) at the point where<br>the Raman relaxation mechanism becomes more important than<br>Orbach.

A Combined Spin-Flip and IP/EA Approach for Handling Spin and Spatial Degeneracies: Application to Double Exchange Systems

2018 ◽  
Author(s):  
Shannon Houck ◽  
Nicholas Mayhall
Keyword(s):  
Single Molecule ◽  
Double Exchange ◽  
Computational Effort ◽  
Strongly Correlated ◽  
Single Molecule Magnets ◽  
New Approach ◽  
Spin Flip ◽  
Model Hamiltonian ◽  
Simultaneous Existence ◽  
Exchange Parameters

<div>Many multiconfigurational systems, such as single-molecule magnets, are difficult to study using traditional computational methods due to the simultaneous existence of both spin and spatial degeneracies. In this work, a new approach termed n-spin-flip Ionization Potential/Electron Affinity (<i>n</i>SF-IP or <i>n</i>SF-EA) is introduced which combines the spin-flip method of Anna Krylov with particle-number changing IP/EA methods. We demonstrate the efficacy of the approach by applying it to the strongly-correlated N<sub>2</sub><sup>+</sup> as well as several double exchange systems. We also demonstrate that when these systems are well-described by a double exchange model Hamiltonian, only 1SF-IP/EA is required to extract the double exchange parameters and accurately predict energies for the low-spin states. This significantly reduces the computational effort for studying such systems. The effects of including additional excitations (using a RAS-<i>n</i>SF-IP/EA scheme) are also examined, with particular emphasis on hole and particle excitations.</div>

A Combined Spin-Flip and IP/EA Approach for Handling Spin and Spatial Degeneracies: Application to Double Exchange Systems

2018 ◽  
Author(s):  
Shannon Houck ◽  
Nicholas Mayhall
Keyword(s):  
Single Molecule ◽  
Double Exchange ◽  
Computational Effort ◽  
Strongly Correlated ◽  
Single Molecule Magnets ◽  
New Approach ◽  
Spin Flip ◽  
Model Hamiltonian ◽  
Simultaneous Existence ◽  
Exchange Parameters

<div>Many multiconfigurational systems, such as single-molecule magnets, are difficult to study using traditional computational methods due to the simultaneous existence of both spin and spatial degeneracies. In this work, a new approach termed n-spin-flip Ionization Potential/Electron Affinity (<i>n</i>SF-IP or <i>n</i>SF-EA) is introduced which combines the spin-flip method of Anna Krylov with particle-number changing IP/EA methods. We demonstrate the efficacy of the approach by applying it to the strongly-correlated N<sub>2</sub><sup>+</sup> as well as several double exchange systems. We also demonstrate that when these systems are well-described by a double exchange model Hamiltonian, only 1SF-IP/EA is required to extract the double exchange parameters and accurately predict energies for the low-spin states. This significantly reduces the computational effort for studying such systems. The effects of including additional excitations (using a RAS-<i>n</i>SF-IP/EA scheme) are also examined, with particular emphasis on hole and particle excitations.</div>

Hydrazone-based Dysprosium Single Molecule Magnets

2013 ◽  
Vol 3 (2) ◽  
pp. 101-111 ◽  
Author(s):  
Peng Zhang ◽  
Li Zhang ◽  
Jinkui Tang
Keyword(s):  
Single Molecule ◽  
Single Molecule Magnets

The localized electron: magnetic properties

2018 ◽  
Author(s):  
Jean-Pierre Launay ◽  
Michel Verdaguer
Keyword(s):  
Single Molecule ◽  
Model Systems ◽  
Ferromagnetic Coupling ◽  
Single Chain ◽  
Single Molecule Magnets ◽  
Magnetic Systems ◽  
Orbital Interactions ◽  
Prussian Blue Analogues ◽  
Mononuclear Complexes

After preliminaries about electron properties, and definitions in magnetism, one treats the magnetism of mononuclear complexes, in particular spin cross-over, showing the role of cooperativity and the sensitivity to external perturbations. Orbital interactions and exchange interaction are explained in binuclear model systems, using orbital overlap and orthogonality concepts to explain antiferromagnetic or ferromagnetic coupling. The phenomenologically useful Spin Hamiltonian is defined. The concepts are then applied to extended molecular magnetic systems, leading to molecular magnetic materials of various dimensionalities exhibiting bulk ferro- or ferrimagnetism. An illustration is provided by Prussian Blue analogues. Magnetic anisotropy is introduced. It is shown that in some cases, a slow relaxation of magnetization arises and gives rise to appealing single-ion magnets, single-molecule magnets or single-chain magnets, a route to store information at the molecular level.

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