The Experts below are selected from a list of 181332 Experts worldwide ranked by ideXlab platform
Wolfgang Wernsdorfer - One of the best experts on this subject based on the ideXlab platform.
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Strong Axiality and Ising Exchange Interaction Suppress Zero-Field Tunneling of Magnetization of an Asymmetric Dy-2 Single-Molecule Magnet
Journal of the American Chemical Society, 2011Co-Authors: Yunnan Guo, Liviu F. Chibotaru, Liviu Ungur, Wolfgang Wernsdorfer, Jinkui Tang, Hongjie Zhang, Annie K PowellAbstract:The high axiality and Ising Exchange Interaction efficiently suppress quantum tunneling of magnetization of an asymmetric dinuclear Dy-III complex, as revealed by combined experimental and theoretical investigations. Two distinct regimes of blockage of magnetization, one originating from the blockage at individual Dy sites and the other due to the Exchange Interaction between the sites, are separated for the first time. The latter contribution is found to be crucial, allowing an increase of the relaxation time by 3 orders of magnitude.
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strong axiality and ising Exchange Interaction suppress zero field tunneling of magnetization of an asymmetric dy2 single molecule magnet
Journal of the American Chemical Society, 2011Co-Authors: Yunnan Guo, Liviu F. Chibotaru, Liviu Ungur, Wolfgang Wernsdorfer, Yang Guo, Jinkui Tang, Hongjie Zhang, Annie K PowellAbstract:The high axiality and Ising Exchange Interaction efficiently suppress quantum tunneling of magnetization of an asymmetric dinuclear Dy(III) complex, as revealed by combined experimental and theoretical investigations. Two distinct regimes of blockage of magnetization, one originating from the blockage at individual Dy sites and the other due to the Exchange Interaction between the sites, are separated for the first time. The latter contribution is found to be crucial, allowing an increase of the relaxation time by 3 orders of magnitude.
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Influence of antisymmetric Exchange Interaction on quantum tunneling of magnetization in a dimeric molecular magnet Mn-6
Physical Review B: Condensed Matter and Materials Physics, 2008Co-Authors: Stefan Bahr, Constantinos J. Milios, L. F. Jones, E.k. Brechin, V. Mosser, Wolfgang WernsdorferAbstract:We present magnetization measurements on the single molecule magnet Mn-6, revealing various tunnel transitions inconsistent with a giant-spin description. We propose a dimeric model of the molecule with two coupled spins S=6, which involves crystal-field anisotropy, symmetric Heisenberg Exchange Interaction, and antisymmetric Dzyaloshinskii-Moriya Exchange Interaction. We show that this simplified model of the molecule explains the experimentally observed tunnel transitions and that the antisymmetric Exchange Interaction between the spins gives rise to tunneling processes between spin states belonging to different spin multiplets.
Annie K Powell - One of the best experts on this subject based on the ideXlab platform.
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Strong Axiality and Ising Exchange Interaction Suppress Zero-Field Tunneling of Magnetization of an Asymmetric Dy-2 Single-Molecule Magnet
Journal of the American Chemical Society, 2011Co-Authors: Yunnan Guo, Liviu F. Chibotaru, Liviu Ungur, Wolfgang Wernsdorfer, Jinkui Tang, Hongjie Zhang, Annie K PowellAbstract:The high axiality and Ising Exchange Interaction efficiently suppress quantum tunneling of magnetization of an asymmetric dinuclear Dy-III complex, as revealed by combined experimental and theoretical investigations. Two distinct regimes of blockage of magnetization, one originating from the blockage at individual Dy sites and the other due to the Exchange Interaction between the sites, are separated for the first time. The latter contribution is found to be crucial, allowing an increase of the relaxation time by 3 orders of magnitude.
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strong axiality and ising Exchange Interaction suppress zero field tunneling of magnetization of an asymmetric dy2 single molecule magnet
Journal of the American Chemical Society, 2011Co-Authors: Yunnan Guo, Liviu F. Chibotaru, Liviu Ungur, Wolfgang Wernsdorfer, Yang Guo, Jinkui Tang, Hongjie Zhang, Annie K PowellAbstract:The high axiality and Ising Exchange Interaction efficiently suppress quantum tunneling of magnetization of an asymmetric dinuclear Dy(III) complex, as revealed by combined experimental and theoretical investigations. Two distinct regimes of blockage of magnetization, one originating from the blockage at individual Dy sites and the other due to the Exchange Interaction between the sites, are separated for the first time. The latter contribution is found to be crucial, allowing an increase of the relaxation time by 3 orders of magnitude.
Liviu F. Chibotaru - One of the best experts on this subject based on the ideXlab platform.
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Giant Exchange Interaction in mixed lanthanides.
Scientific reports, 2016Co-Authors: Veacheslav Vieru, Naoya Iwahara, Liviu Ungur, Liviu F. ChibotaruAbstract:Combining strong magnetic anisotropy with strong Exchange Interaction is a long standing goal in the design of quantum magnets. The lanthanide complexes, while exhibiting a very strong ionic anisotropy, usually display a weak Exchange coupling, amounting to only a few wavenumbers. Recently, an isostructural series of mixed (Ln = Gd, Tb, Dy, Ho, Er) have been reported, in which the Exchange splitting is estimated to reach hundreds wavenumbers. The microscopic mechanism governing the unusual Exchange Interaction in these compounds is revealed here by combining detailed modeling with density-functional theory and ab initio calculations. We find it to be basically kinetic and highly complex, involving non-negligible contributions up to seventh power of total angular momentum of each lanthanide site. The performed analysis also elucidates the origin of magnetization blocking in these compounds. Contrary to general expectations the latter is not always favored by strong Exchange Interaction.
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Ising Exchange Interaction in lanthanides and actinides
New Journal of Physics, 2015Co-Authors: Liviu F. Chibotaru, Naoya IwaharaAbstract:The Ising Exchange Interaction is a limiting case of strong Exchange anisotropy and represents a key property of many magnetic materials. Here we find the necessary and sufficient conditions to achieve Ising Exchange Interaction for metal sites with unquenched orbital moments. Contrary to current views, the rules established here narrow much the range of lanthanide and actinide ions that can exhibit Ising Exchange Interaction. It is shown that the Ising Interaction can be of two types: (i) coaxial, with magnetic moments directed along the anisotropy axes on the metal sites and (ii) non-coaxial, with arbitrary orientation of one of the magnetic moments. These findings will contribute to purposeful design of lanthanide- and actinide-based materials.
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Exchange Interaction between J-multiplets
Physical Review B, 2015Co-Authors: Naoya Iwahara, Liviu F. ChibotaruAbstract:Analytical expressions for the Exchange Interaction between $J$-multiplets of interacting metallic centers are derived on the basis of a complete electronic model. A common belief that this Interaction can be approximated by an isotropic form $\propto {\mathbf{J}}_1\cdot{\mathbf{J}}_2$ (or $\propto {\mathbf{J}}_1\cdot{\mathbf{S}}_2$ in the case of Interaction with an isotropic spin) is found to be ungrounded. It is also shown that the often used "1/U approximation" for the description of the kinetic contribution of the Exchange Interaction is not valid in the case of $J$-multiplets. The developed theory can be used for microscopic description of Exchange Interaction in materials containing lanthanides, actinides and some transition metal ions.
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Strong Axiality and Ising Exchange Interaction Suppress Zero-Field Tunneling of Magnetization of an Asymmetric Dy-2 Single-Molecule Magnet
Journal of the American Chemical Society, 2011Co-Authors: Yunnan Guo, Liviu F. Chibotaru, Liviu Ungur, Wolfgang Wernsdorfer, Jinkui Tang, Hongjie Zhang, Annie K PowellAbstract:The high axiality and Ising Exchange Interaction efficiently suppress quantum tunneling of magnetization of an asymmetric dinuclear Dy-III complex, as revealed by combined experimental and theoretical investigations. Two distinct regimes of blockage of magnetization, one originating from the blockage at individual Dy sites and the other due to the Exchange Interaction between the sites, are separated for the first time. The latter contribution is found to be crucial, allowing an increase of the relaxation time by 3 orders of magnitude.
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strong axiality and ising Exchange Interaction suppress zero field tunneling of magnetization of an asymmetric dy2 single molecule magnet
Journal of the American Chemical Society, 2011Co-Authors: Yunnan Guo, Liviu F. Chibotaru, Liviu Ungur, Wolfgang Wernsdorfer, Yang Guo, Jinkui Tang, Hongjie Zhang, Annie K PowellAbstract:The high axiality and Ising Exchange Interaction efficiently suppress quantum tunneling of magnetization of an asymmetric dinuclear Dy(III) complex, as revealed by combined experimental and theoretical investigations. Two distinct regimes of blockage of magnetization, one originating from the blockage at individual Dy sites and the other due to the Exchange Interaction between the sites, are separated for the first time. The latter contribution is found to be crucial, allowing an increase of the relaxation time by 3 orders of magnitude.
Yunnan Guo - One of the best experts on this subject based on the ideXlab platform.
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Strong Axiality and Ising Exchange Interaction Suppress Zero-Field Tunneling of Magnetization of an Asymmetric Dy-2 Single-Molecule Magnet
Journal of the American Chemical Society, 2011Co-Authors: Yunnan Guo, Liviu F. Chibotaru, Liviu Ungur, Wolfgang Wernsdorfer, Jinkui Tang, Hongjie Zhang, Annie K PowellAbstract:The high axiality and Ising Exchange Interaction efficiently suppress quantum tunneling of magnetization of an asymmetric dinuclear Dy-III complex, as revealed by combined experimental and theoretical investigations. Two distinct regimes of blockage of magnetization, one originating from the blockage at individual Dy sites and the other due to the Exchange Interaction between the sites, are separated for the first time. The latter contribution is found to be crucial, allowing an increase of the relaxation time by 3 orders of magnitude.
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strong axiality and ising Exchange Interaction suppress zero field tunneling of magnetization of an asymmetric dy2 single molecule magnet
Journal of the American Chemical Society, 2011Co-Authors: Yunnan Guo, Liviu F. Chibotaru, Liviu Ungur, Wolfgang Wernsdorfer, Yang Guo, Jinkui Tang, Hongjie Zhang, Annie K PowellAbstract:The high axiality and Ising Exchange Interaction efficiently suppress quantum tunneling of magnetization of an asymmetric dinuclear Dy(III) complex, as revealed by combined experimental and theoretical investigations. Two distinct regimes of blockage of magnetization, one originating from the blockage at individual Dy sites and the other due to the Exchange Interaction between the sites, are separated for the first time. The latter contribution is found to be crucial, allowing an increase of the relaxation time by 3 orders of magnitude.
I S Burmistrov - One of the best experts on this subject based on the ideXlab platform.
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indirect Exchange Interaction between magnetic impurities near the helical edge
Physical Review B, 2017Co-Authors: V D Kurilovich, P D Kurilovich, I S BurmistrovAbstract:The indirect Exchange Interaction between magnetic impurities located in the bulk of a two-dimensional topological insulator decays exponentially with the distance. The indirect Exchange Interaction for magnetic impurities mediated by the helical states at the edge of the topological insulator demonstrates behavior which is typical for the Ruderman-Kittel-Kasuya-Yosida Interaction in a one-dimensional metal. We have shown that interference between the bulk and the edge states in the two-dimensional topological insulator results in existence of an unusual contribution to the indirect Exchange Interaction which, on the one hand, decays exponentially with a distance at the length scale controlled by the Fermi energy of the edge states and, on the other hand, oscillates with distance along the helical edge with the period determined by the Fermi wavelength. We found that this interference contribution to the indirect Exchange Interaction becomes dominant for such configurations of two magnetic impurities that one of them is situated close to the helical edge whereas the other one is located far away in the bulk.
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indirect Exchange Interaction between magnetic impurities in the two dimensional topological insulator based on cdte hgte cdte quantum wells
Physical Review B, 2016Co-Authors: V D Kurilovich, P D Kurilovich, I S BurmistrovAbstract:We study indirect Exchange Interaction between magnetic impurities in the (001) CdTe/HgTe/CdTe symmetric quantum well. We consider low temperatures and the case of the chemical potential placed in the energy gap of the two-dimensional quasiparticle spectrum. We find that the indirect Exchange Interaction is suppressed exponentially with the distance between magnetic impurities. The presence of inversion asymmetry results in oscillations of the indirect Exchange Interaction with the distance and generates additional terms which are noninvariant under rotations in the (001) plane. The indirect Exchange Interaction matrix has complicated structure with some terms proportional to the sign of the energy gap.
