Enhancing the barrier height for Yb(iii) single-ion magnets by modulating axial ligand fields

2020 ◽  
Vol 56 (79) ◽  
pp. 11879-11882 ◽  
Author(s):  
Aditya Borah ◽  
Sourav Dey ◽  
Sandeep K. Gupta ◽  
Mrinalini G. Walawalkar ◽  
Gopalan Rajaraman ◽  
...  
Keyword(s):  
Barrier Height ◽  
Axial Ligand ◽  
Ligand Field ◽  
Magnetic Reversal ◽  
Ligand Fields

Progressive weakening of the axial ligand field, by keeping the equatorial field constant, enhances the barrier height for magnetic reversal in six-coordinate pseudo-octahedral Yb(iiii) single ion magnets.

scholarly journals Breaching the Axial Limits in Ln(III) Single-Ion Magnets Using External Electric Field

2020 ◽  
Author(s):  
Arup Sarkar ◽  
Rajaraman Gopalan
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Barrier Height ◽  
Electric Fields ◽  
Single Molecule ◽  
Information Storage ◽  
Fine Tuning ◽  
Ligand Field ◽  
Nano Technology ◽  
Technology Applications

<i>Single-Molecule Magnets have potential applications in several nano-technology applications including in high-dense information storage devices and realization of this potential application lies in enhancing the barrier height for magnetization reversal (U<sub>eff</sub>). Recent literature examples suggest that the maximum values that one can obtain using a ligand field are already accomplished. Here we have explored using a combination of DFT and ab initio CASSCF calculations, the way to enhance the barrier height using an oriented external electric field for top three Single-ion Magnets ([Dy(Py)<sub>5</sub>(O<sup>t</sup>Bu)<sub>2</sub>]<sup>+</sup> (<b>1</b>) and [Er{N(SiMe<sub>3</sub>)<sub>2</sub>}<sub>3</sub>Cl]<sup>-</sup> (<b>2</b>) and [Dy(Cp<sup>Me3</sup>)Cl] (<b>3</b>)). For the first time our study reveals that, for apt molecules, if appropriate direction and value of electric fields are chosen, the barrier height could be enhanced twice that of the limit set by the ligand field. This novel non-chemical-fine tuning approach to modulate the magnetic anisotropy is expected to yield new generation SIMs.</i>

Ligand field effects on the ground and excited states of reactive FeO2+ species

2018 ◽  
Vol 20 (45) ◽  
pp. 28786-28795 ◽  
Author(s):  
Justin K. Kirkland ◽  
Shahriar N. Khan ◽  
Bryan Casale ◽  
Evangelos Miliordos ◽  
Konstantinos D. Vogiatzis
Keyword(s):  
Iron Oxide ◽  
Quantum Chemical Calculations ◽  
Excited States ◽  
Quantum Chemical ◽  
Ligand Field ◽  
Reactive Iron ◽  
Field Effects ◽  
Ligand Fields

Multiconfigurational quantum chemical calculations on bare and representative ligated iron oxide dicationic species suggest that weak ligand fields promote more reactive channels, whereas strong ligand fields stabilize the less reactive iron-oxo structure.

Pseudohalogenido complexes of iron-2,2′-bidipyrrins

2012 ◽  
Vol 16 (05n06) ◽  
pp. 641-650 ◽  
Author(s):  
Martin Bröring ◽  
Silke Köhler ◽  
Clemens Pietzonka
Keyword(s):  
High Spin ◽  
Spin State ◽  
Elevated Temperatures ◽  
High Spin State ◽  
Spectroscopic Studies ◽  
Axial Ligand ◽  
Ligand Field ◽  
Central Metal ◽  
Exchange Reactions ◽  
Dichloromethane Solution

The chlorido iron(III) complex of octaethyl-2,2′-bidipyrrin has been transformed to a series of pseudohalide complexes by ligand exchange reactions with azide, cyanate, thiocyanate and selenocyanate anions. All new complexes show the expected N-coordination of the axial ligand to the iron(III) center. In the solid state, all four species display an intermediate spin (S = 3/2) ground state, with a gradual increase of a high spin (S = 5/2) contribution at elevated temperatures for the members with the smallest ligand field strengths, i.e. the cyanato and the azido derivatives. In solution, proton NMR, and in particular IR spectroscopic studies support the interpretation of a high-spin state at ambient temperature throughout the series. The dependency of the spin state on the crystalline or dissolved state thus resembles that found for a similar series of halide derivatives before. In dichloromethane solution, the thiocyanato and selenocyanato complexes are very sensitive to aerial oxidation, forming oxacorrole and thiacorrole complexes as the only isolated products. These complexes show a S = 3/2 spin state in the solid as well as in solution, and their structural analyses prove the expected strong π-binding of the linear pseudohalide ion to the iron(III) central metal.

The d2 and d8 Noncubic Ligand Field Spectrum. I. The Complete Theory of Quadrate, Trigonal, and Cylindrical Ligand Fields

1972 ◽  
Vol 27 (12) ◽  
pp. 1820-1860 ◽  
Author(s):  
Jayarama Perumareddi
Keyword(s):  
Cylindrical Symmetry ◽  
Complete Theory ◽  
Ligand Field ◽  
Spin Orbit ◽  
Planar Limit ◽  
Unitary Transformations ◽  
Cubic Fields ◽  
Electronic Configurations ◽  
Tetrahedral Complexes ◽  
Ligand Fields

AbstractThe complete theory of Liehr and Ballhausen for d2 and d8 electronic configurations immersed in cubic fields has been extended to include noncubic ligand fields of quadrate, trigonal, and cylindrical symmetry. The complete set of symmetry adapted eigenvectors for the three symmetries have been derived in various coupling schemes in which the spin-orbit interaction, electron cor-relation, and ligand field in turn are varied from minor to dominant perturbations. The cor-responding energy matrices as a function of the parameters of the ligand field, electron correlation, and spin-orbit constant have been constructed in all the representations. Unitary transformations connecting different formalisms were obtained. The energy matrices have been solved for representative sets of parametric values and energy diagrams have been plotted in all the symmetries as well as in the square planar limit of the quadrate crystalline field. The secular determinants, the eigenfunctions, the energy diagrams, and the unitary transformations presented here are extremely useful in the study of the various aspects of spectroscopic, magnetic, and other properties of appropriate systems. The theory is applicable to quadrately distorted or substituted, trigonally distorted or substituted, octahedral and tetrahedral complexes and to compounds of cylindrical symmetry of d2 and d8 electronic configurations.

scholarly journals Breaching the Axial Limits in Ln(III) Single-Ion Magnets Using External Electric Field

2020 ◽  
Author(s):  
Arup Sarkar ◽  
Rajaraman Gopalan
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Barrier Height ◽  
Electric Fields ◽  
Single Molecule ◽  
Information Storage ◽  
Fine Tuning ◽  
Ligand Field ◽  
Nano Technology ◽  
Technology Applications

<i>Single-Molecule Magnets have potential applications in several nano-technology applications including in high-dense information storage devices and realization of this potential application lies in enhancing the barrier height for magnetization reversal (U<sub>eff</sub>). Recent literature examples suggest that the maximum values that one can obtain using a ligand field are already accomplished. Here we have explored using a combination of DFT and ab initio CASSCF calculations, the way to enhance the barrier height using an oriented external electric field for top three Single-ion Magnets ([Dy(Py)<sub>5</sub>(O<sup>t</sup>Bu)<sub>2</sub>]<sup>+</sup> (<b>1</b>) and [Er{N(SiMe<sub>3</sub>)<sub>2</sub>}<sub>3</sub>Cl]<sup>-</sup> (<b>2</b>) and [Dy(Cp<sup>Me3</sup>)Cl] (<b>3</b>)). For the first time our study reveals that, for apt molecules, if appropriate direction and value of electric fields are chosen, the barrier height could be enhanced twice that of the limit set by the ligand field. This novel non-chemical-fine tuning approach to modulate the magnetic anisotropy is expected to yield new generation SIMs.</i>

scholarly journals Axial Ligand Field in D4d Coordination Symmetry: Magnetic Relaxation of Dy SMMs Perturbed by Counteranions

2017 ◽  
Vol 56 (18) ◽  
pp. 11211-11219 ◽  
Author(s):  
Jianfeng Wu ◽  
Olivier Cador ◽  
Xiao-Lei Li ◽  
Lang Zhao ◽  
Boris Le Guennic ◽  
...  
Keyword(s):  
Magnetic Relaxation ◽  
Axial Ligand ◽  
Ligand Field
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