scholarly journals Weak exchange striction between the 4f and 3d ions in the multiferroic GdMn2O5

2019 ◽  
Vol 99 (9) ◽  
Author(s):  
Jieming Sheng ◽  
X. Tong ◽  
Feng Ye ◽  
J. A. Fernandez-Baca ◽  
H. Cao ◽  
...  
Keyword(s):  
Weak Exchange

Giant magnetisation step in Fe 2 : Molecular nanomagnets in the weak exchange limit

2011 ◽  
Vol 95 (5) ◽  
pp. 57002 ◽  
Author(s):  
F. El Hallak ◽  
P. Rosa ◽  
P. Vidal ◽  
I. Sheikin ◽  
M. Dressel ◽  
...  
Keyword(s):  
Molecular Nanomagnets ◽  
Weak Exchange

Theory of spin waves in triangular antiferromagnets

1978 ◽  
Vol 56 (11) ◽  
pp. 1482-1487 ◽  
Author(s):  
J. A. Oyedele ◽  
M. F. Collins
Keyword(s):  
Spin Wave ◽  
Basal Plane ◽  
Exchange Interactions ◽  
Wave Theory ◽  
Wave Dispersion ◽  
One Dimensional ◽  
Dipole Interactions ◽  
Weak Exchange ◽  
Exchange Constants ◽  
Strong Exchange

A simple hexagonal array of classical spins coupled by nearest-neighbour antiferromagnetic Heisenberg interactions has a ground state with a triangular antiferromagnetic configuration of spins. We have developed spin wave theory for triangular antiferromagnets with both Heisenberg and dipole–dipole interactions. The dipole–dipole interactions confine the spins to the hexagonal basal plane and they do not distort the equiangular triangular structure. Spin wave dispersion relations are plotted for some trial values of the exchange constants. The theory is applied to the triangular antiferromagnet CsMnBr3. This is a quasi-one-dimensional material with strong exchange interactions along the hexagonal axes and with weak exchange interactions within the basal plane that are of the same order as dipolar interactions.

An electron spin resonance study of certain vanadyl polyaminocarboxylate chelates formed in aqueous and frozen aqueous solutions

1974 ◽  
Vol 27 (12) ◽  
pp. 2535 ◽  
Author(s):  
TD Smith ◽  
JF Boas ◽  
JR Pilbrow
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Exchange Coupling ◽  
Electron Spin Resonance Study ◽  
Ph Titration ◽  
Weak Exchange ◽  
Spin Resonance ◽  
Dimeric Form ◽  
Firm Evidence ◽  
Spin Resonance Study

Potentiometric pH-titration and electron spin resonance studies have shown the existence of mono-meric, dimeric and dinuclear vanadyl chelates of certain polyaminocarboxylic acids. The ligands studied include ethylenediaminetetraacetic (edta), ethyleneglycolbis(β- aminoethyl ether)-N,N?-tetra-acetic (egta), diethylenetriaminepentaacetic (dtpa) and triethylenetetraaminehexaace- tic (ttha) acids. All the ligands form 1 : 1 chelates. The addition of ethylene glycol to the aqueous solution in each case provides circumstances for the study of the monomeric chelates, though it is not equally effective in all cases. The 1 : 1 vanadyl egta chelate above pH 5.5 gave rise to ΔMS = � 2 and ΔMS = � 1 transitions from which structural and magnetic parameters have been determined and interpreted in terms of the formation of a dimeric form of a hydrolytic product of the 1 : 1 chelate. Firm evidence for the formation of dinuclear chelates occurs only in the vanadyl ttha system. Here the room tem- perature e.s.r. spectrum shows the presence of weak exchange coupling between the vanadyl ions in the dinuclear chelate.

Magnetism of Spin System with Alternating Strong and Weak Exchange Coupling. I. Theoretical Study

1981 ◽  
Vol 50 (11) ◽  
pp. 3583-3587 ◽  
Author(s):  
Shigeru Takatori ◽  
Naoshi Suzuki ◽  
Kazuko Motizuki
Keyword(s):  
Spin System ◽  
Exchange Coupling ◽  
Theoretical Study ◽  
Weak Exchange

scholarly journals Temperature-dependent optical conductivity of undoped cuprates with weak exchange

2008 ◽  
Vol 78 (6) ◽  
Author(s):  
J. Málek ◽  
S.-L. Drechsler ◽  
U. Nitzsche ◽  
H. Rosner ◽  
H. Eschrig
Keyword(s):  
Optical Conductivity ◽  
Temperature Dependent ◽  
Weak Exchange

ANDREEV SPECTRUM AND SUPERCURRENT IN A DOUBLE FERROMAGNET CLEAN JOSEPHSON JUNCTION

2007 ◽  
Vol 21 (09) ◽  
pp. 505-529 ◽  
Author(s):  
V. PALTOGLOU ◽  
I. MARGARIS ◽  
N. FLYTZANIS
Keyword(s):  
Energy Spectrum ◽  
Bound States ◽  
Reasonable Agreement ◽  
Double Resonance ◽  
Exchange Field ◽  
Extensive Investigation ◽  
Andreev Bound States ◽  
Weak Exchange ◽  
Interface Potential ◽  
Analytical Formulas

We consider a superconductor/double-ferromagnet/superconductor (S/I1/F/IC/F'/I2/S) ballistic junction with thin insulating layers in the interfaces. An extensive investigation is carried out for the possibility of 0- or π-junction and the important phaseshift. The average exchange field for the two ferromagnets has limited use, only for weak exchange fields. Several analytical formulas are obtained for the energy spectrum in simple cases with interface potential (a) absent, (b) between ferromagnets only, (c) double resonance barrier between S and F layers. They give reasonable agreement even outside their range of validity. For the case of strong S/F barriers we find a strong interplay of Andreev bound states and interbarrier resonances.

scholarly journals Synthesis and Characterisation of New Symmetrical Binucleating Ligands and Their Binuclear Copper(II) Complexes

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
K. Jothivenkatachalam ◽  
S. Chandra Mohan
Keyword(s):  
Electron Transfer ◽  
Exchange Interaction ◽  
Variable Temperature ◽  
Esr Spectra ◽  
Single Step ◽  
Binuclear Copper ◽  
Magnetic Studies ◽  
Weak Exchange ◽  
Broad Signal ◽  
Binucleating Ligands

New symmetrical binucleating ligands N,N-bis[2-hydroxy-5-methyl-3-(4-methyl-piperazinomethyl)benzyl]-alkylamines L1 and L2 and their copper(II) complexes [Cu2L(X)2]·2H2O, where X = CH3COO−, C6H5COO−, Cl−, and ClO4-, were prepared and characterised. All the complexes undergo quasi-reversible reduction at negative potential (E = −0.48 to −1.02 V). The acetate and benzoate complexes undergo a two-step single electron transfer at –0.48 to –0.60 V and −0.9 to −1.02 V. The chloro and perchlorate complexes undergo a single step two-electron transfer at −0.55 to −0.75 V. Variable temperature magnetic studies show the presence of weak exchange interaction for acetate (−2 J around 25 to 40 cm−1) and benzoate (−2 J around 45 to 55 cm−1) bridged complexes and no exchange interaction is found for chloro and perchlorate complexes. ESR spectra of chloro and perchlorate complexes are like mononuclear copper(II) complexes with hyperfine splitting (A = 165 ± 5, g∥ = 2.17–2.23, and g⊥ = 2.05–2.10). The ESR spectra of acetate and benzoate complexes are like binuclear copper(II) complexes with broad signal (g = 2.2).

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