scholarly journals Exchange interactions and high-energy spin states inMn12-acetate

2004 ◽  
Vol 70 (10) ◽  
Author(s):  
G. Chaboussant ◽  
A. Sieber ◽  
S. Ochsenbein ◽  
H.-U. Güdel ◽  
M. Murrie ◽  
...  
Keyword(s):  
Exchange Interactions ◽  
High Energy ◽  
Spin States

Temperature evolution of frustrated spin states in the system with competing exchange interactions. Fe0.65Ni0.35)1−x Mnx (x=0, 0.024, 0.034)

1998 ◽  
Vol 40 (9) ◽  
pp. 1500-1505
Author(s):  
N. N. Delyagin ◽  
A. L. Erzinkyan ◽  
V. P. Parfenova ◽  
S. I. Reiman ◽  
G. M. Gurevich ◽  
...  
Keyword(s):  
Exchange Interactions ◽  
Temperature Evolution ◽  
Spin States ◽  
Frustrated Spin

scholarly journals Spiky strings in de Sitter space

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Mitsuhiro Kato ◽  
Kanji Nishii ◽  
Toshifumi Noumi ◽  
Toshiaki Takeuchi ◽  
Siyi Zhou
Keyword(s):  
Regge Trajectory ◽  
Flat Space ◽  
De Sitter Space ◽  
High Energy ◽  
Spin States ◽  
De Sitter ◽  
Regge Trajectories ◽  
Higher Spin ◽  
Maximum Spin

Abstract We study semiclassical spiky strings in de Sitter space and the corresponding Regge trajectories, generalizing the analysis in anti-de Sitter space. In particular we demonstrate that each Regge trajectory has a maximum spin due to de Sitter acceleration, similarly to the folded string studied earlier. While this property is useful for the spectrum to satisfy the Higuchi bound, it makes a nontrivial question how to maintain mildness of high-energy string scattering which we are familiar with in flat space and anti-de Sitter space. Our analysis implies that in order to have infinitely many higher spin states, one needs to consider infinitely many Regge trajectories with an increasing folding number.

A single chain magnet involving hexacyanoosmate

2014 ◽  
Vol 50 (54) ◽  
pp. 7150-7153 ◽  
Author(s):  
Eugenia V. Peresypkina ◽  
Anna M. Majcher ◽  
Michał Rams ◽  
Kira E. Vostrikova
Keyword(s):  
Magnetic Anisotropy ◽  
Exchange Interactions ◽  
High Energy ◽  
Single Chain ◽  
Energy Barriers ◽  
Paramagnetic Centres

The first single chain magnet (SCM) based on the orbitally degenerate [Os(CN)6]3− anion was prepared. The high energy barriers are a result of interplay of Mn3+ single-ion magnetic anisotropy and highly anisotropic three axes exchange interactions between the paramagnetic centres.

scholarly journals Spin Structures in Magnetic Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Steen Mørup ◽  
Erik Brok ◽  
Cathrine Frandsen
Keyword(s):  
Low Temperatures ◽  
Particle Surface ◽  
Exchange Interactions ◽  
Short Review ◽  
Spin Reorientation ◽  
Spin States ◽  
Anomalous Temperature ◽  
Spin Structures ◽  
Canted Spin ◽  
Temperature Dependences

Spin structures in nanoparticles of ferrimagnetic materials may deviate locally in a nontrivial way from ideal collinear spin structures. For instance, magnetic frustration due to the reduced numbers of magnetic neighbors at the particle surface or around defects in the interior can lead to spin canting and hence a reduced magnetization. Moreover, relaxation between almost degenerate canted spin states can lead to anomalous temperature dependences of the magnetization at low temperatures. In ensembles of nanoparticles, interparticle exchange interactions can also result in spin reorientation. Here, we give a short review of anomalous spin structures in nanoparticles.

scholarly journals Tris(Butadiene) Compounds versus Butadiene Oligomerization in Second-Row Transition Metal Chemistry: Effects of Increased Ligand Fields

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2220
Author(s):  
Yi Zhao ◽  
Qun Chen ◽  
Mingyang He ◽  
Zhihui Zhang ◽  
Xuejun Feng ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Density Functional ◽  
High Energy ◽  
Low Energy ◽  
Central Metal Atom ◽  
Central Metal ◽  
Spin States ◽  
Open Chain ◽  
Spin Singlet

The geometries, energetics, and preferred spin states of the second-row transition metal tris(butadiene) complexes (C4H6)3M (M = Zr–Pd) and their isomers, including the experimentally known very stable molybdenum derivative (C4H6)3Mo, have been examined by density functional theory. Such low-energy structures are found to have low-spin singlet and doublet spin states in contrast to the corresponding derivatives of the first-row transition metals. The three butadiene ligands in the lowest-energy (C4H6)3M structures of the late second-row transition metals couple to form a C12H18 ligand that binds to the central metal atom as a hexahapto ligand for M = Pd but as an octahapto ligand for M = Rh and Ru. However, the lowest-energy (C4H6)3M structures of the early transition metals have three separate tetrahapto butadiene ligands for M = Zr, Nb, and Mo or two tetrahapto butadiene ligands and one dihapto butadiene ligand for M = Tc. The low energy of the experimentally known singlet (C4H6)3Mo structure contrasts with the very high energy of its experimentally unknown singlet chromium (C4H6)3Cr analog relative to quintet (C12H18)Cr isomers with an open-chain C12H18 ligand.

The E-ring: interactions with plasma and implications for its evolution

1984 ◽  
Vol 75 ◽  
pp. 599-602
Author(s):  
T.V. Johnson ◽  
G.E. Morfill ◽  
E. Grun
Keyword(s):  
Time Scale ◽  
Particle Density ◽  
High Energy ◽  
Particle Removal ◽  
Density Region ◽  
Drag Forces ◽  
Orbit Evolution ◽  
History Of ◽  
Ring Particle ◽  
Ring Material

A number of lines of evidence suggest that the particles making up the E-ring are small, on the order of a few microns or less in size (Terrile and Tokunaga, 1980, BAAS; Pang et al., 1982 Saturn meeting; Tucson, AZ). This suggests that a variety of electromagnetic and plasma affects may be important in considering the history of such particles. We have shown (Morfill et al., 1982, J. Geophys. Res., in press) that plasma drags forces from the corotating plasma will rapidly evolve E-ring particle orbits to increasing distance from Saturn until a point is reached where radiation drag forces acting to decrease orbital radius balance this outward acceleration. This occurs at approximately Rhea's orbit, although the exact value is subject to many uncertainties. The time scale for plasma drag to move particles from Enceladus' orbit to the outer E-ring is ~104yr. A variety of effects also act to remove particles, primarily sputtering by both high energy charged particles (Cheng et al., 1982, J. Geophys. Res., in press) and corotating plasma (Morfill et al., 1982). The time scale for sputtering away one micron particles is also short, 102 - 10 yrs. Thus the detailed particle density profile in the E-ring is set by a competition between orbit evolution and particle removal. The high density region near Enceladus' orbit may result from the sputtering yeild of corotating ions being less than unity at this radius (e.g. Eviatar et al., 1982, Saturn meeting). In any case, an active source of E-ring material is required if the feature is not very ephemeral - Enceladus itself, with its geologically recent surface, appears still to be the best candidate for the ultimate source of E-ring material.

Analysis of electron-diffraction intensity profiles using a photodiode-array detection system

1983 ◽  
Vol 41 ◽  
pp. 322-323
Author(s):  
J. B. Warren
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Detection System ◽  
High Energy ◽  
Photographic Emulsion ◽  
Diffraction Intensity ◽  
Silicon Photodiode ◽  
Photodiode Array Detection ◽  
Analog To Digital ◽  
Photodiode Array

Electron diffraction intensity profiles have been used extensively in studies of polycrystalline and amorphous thin films. In previous work, diffraction intensity profiles were quantitized either by mechanically scanning the photographic emulsion with a densitometer or by using deflection coils to scan the diffraction pattern over a stationary detector. Such methods tend to be slow, and the intensities must still be converted from analog to digital form for quantitative analysis. The Instrumentation Division at Brookhaven has designed and constructed a electron diffractometer, based on a silicon photodiode array, that overcomes these disadvantages. The instrument is compact (Fig. 1), can be used with any unmodified electron microscope, and acquires the data in a form immediately accessible by microcomputer.Major components include a RETICON 1024 element photodiode array for the de tector, an Analog Devices MAS-1202 analog digital converter and a Digital Equipment LSI 11/2 microcomputer. The photodiode array cannot detect high energy electrons without damage so an f/1.4 lens is used to focus the phosphor screen image of the diffraction pattern on to the photodiode array.

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