Spin fluctuations in random magnetic-nonmagnetic two-dimensional antiferromagnets. II. Heisenberg percolation

1980 ◽  
Vol 21 (1) ◽  
pp. 317-332 ◽  
Author(s):  
R. J. Birgeneau ◽  
R. A. Cowley ◽  
G. Shirane ◽  
J. A. Tarvin ◽  
H. J. Guggenheim
Keyword(s):  
Spin Fluctuations ◽  
Two Dimensional

Magnetic Properties and Spin Kinetics of Two-Dimensional Heisenberg Antiferromagnets

2003 ◽  
Vol 17 (10n12) ◽  
pp. 487-490
Author(s):  
S. I. Belov ◽  
B. I. Kochelaev
Keyword(s):  
Order Parameter ◽  
Spin Fluctuations ◽  
Local Order ◽  
Nuclear Relaxation ◽  
Two Dimensional ◽  
Nuclear Spins ◽  
Static Magnetic Susceptibility ◽  
Spin Excitations ◽  
Local Order Parameter ◽  
Kinetics Of

In this report we present our study of two-dimensional Heisenberg magnets based on the picture of thermally excited skyrmions. The local order parameter, energy spectrum of elementary spin excitations above the skyrmion background, the skyrmion averaged radius and static magnetic susceptibility were obtained by the Green functions method. There was calculated the rate of nuclear relaxation caused by the interaction of nuclear spins with above mentioned spin excitations. The contribution of Moriya–Dsyloshinskii and anisotropic symmetric interactions into EPR line was considered. A comparison with NMR and neutron scattering experiments in cuprates and with the results obtained by other methods is given. We discuss the consequences of an interaction between skyrmions as the result of the spin fluctuations.

scholarly journals Anomalous spin correlations and excitonic instability of interacting 2D Weyl fermions

Science ◽  
2017 ◽  
Vol 358 (6369) ◽  
pp. 1403-1406 ◽  
Author(s):  
Michihiro Hirata ◽  
Kyohei Ishikawa ◽  
Genki Matsuno ◽  
Akito Kobayashi ◽  
Kazuya Miyagawa ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Nmr Relaxation ◽  
Spin Fluctuations ◽  
Two Dimensional ◽  
Marked Contrast ◽  
Metallic Behavior ◽  
Model Calculations ◽  
Spin Correlations ◽  
Zero Momentum ◽  
Weyl Fermions

The Coulomb interaction in systems of quasi-relativistic massless electrons has an unscreened long-range component at variance with conventional correlated metals. We used nuclear magnetic resonance (NMR) measurements to reveal unusual spin correlations of two-dimensional Weyl fermions in an organic material, causing a divergent increase of the Korringa ratio by a factor of 1000 upon cooling, in marked contrast to conventional metallic behavior. Combined with model calculations, we show that this divergence stems from an interaction-driven velocity renormalization that almost exclusively suppresses zero-momentum spin fluctuations. At low temperatures, the NMR relaxation rate shows an unexpected increase; numerical analyses show that this increase corresponds to internode excitonic fluctuations, a precursor to a transition from massless to massive quasiparticles.

scholarly journals SCHWINGER-BOSON STUDIES OF THE SINGLE HOLE MOTION IN A 2D QUANTUM ANTIFERROMAGNET

1994 ◽  
Vol 08 (27) ◽  
pp. 3843-3858
Author(s):  
C.Q. WU ◽  
Z.B. SU ◽  
L. YU
Keyword(s):  
Heisenberg Model ◽  
Quantum Spin ◽  
Spin Fluctuations ◽  
Energy Separation ◽  
Antiferromagnetic Order ◽  
Two Dimensional ◽  
Equal Footing ◽  
Anisotropic Heisenberg Model ◽  
Single Hole ◽  
Quantum Antiferromagnet

Within the Schwinger-boson approach for the t-J model, the single hole problem in a two-dimensional quantum antiferromagnet is studied by using the quantum Bogoliubovde Gennes formalism which treats the distortion of the spin background and quantum spin fluctuations on an equal footing. Several self-trapped localized hole states are found in the distorted spin-background as in the case of an anisotropic Heisenberg model. These localized hole states survive at finite temperatures when the antiferromagnetic order becomes short-ranged. The energy separation between the two lowest states is reduced by considering the spin-background distortion, but it remains finite.

Spin fluctuations in a two-dimensional marginal Fermi liquid

1993 ◽  
Vol 48 (1) ◽  
pp. 487-498 ◽  
Author(s):  
P. B. Littlewood ◽  
J. Zaanen ◽  
G. Aeppli ◽  
H. Monien
Keyword(s):  
Fermi Liquid ◽  
Spin Fluctuations ◽  
Two Dimensional ◽  
Marginal Fermi Liquid

TWO-DIMENSIONAL FERROMAGNETIC ORDERING IN A METAL–ORGANIC MULTILAYER STRUCTURE

2005 ◽  
Vol 04 (05n06) ◽  
pp. 831-837 ◽  
Author(s):  
M. K. SANYAL ◽  
M. K. MUKHOPADHYAY ◽  
R. M. DALGLIESH ◽  
S. LANGRIDGE
Keyword(s):  
Magnetic Measurements ◽  
Spontaneous Magnetization ◽  
Spin Fluctuations ◽  
Neutron Reflectivity ◽  
Two Dimensional ◽  
Crystalline Anisotropy ◽  
Theoretical Predictions ◽  
Metal Organic ◽  
Plane Direction ◽  
Ferromagnetic Ordering

We demonstrate, using spin polarized neutron reflectivity measurements, that one can form a large stack of magnetically decoupled spin-membranes of Gadolinium ions and reduce the effect of the substrate substantially to study short-range two-dimensional (2D) ferromagnetic ordering. No spontaneous magnetization was observed in these membranes as the magnetic field was applied along an in-plane direction. The results are consistent with theoretical predictions of 2D in-plane spin systems having strong interplay of exchange, magneto-crystalline anisotropy and dipolar interactions. These metal–organic multilayer films will enable us to verify various theoretical predictions regarding spin-fluctuations in 2D systems using conventional magnetic measurements and neutron scattering studies.

scholarly journals Spin fluctuations with two-dimensional XY behavior in a frustratedS=12square-lattice ferromagnet

2013 ◽  
Vol 87 (18) ◽  
Author(s):  
T. Förster ◽  
F. A. Garcia ◽  
T. Gruner ◽  
E. E. Kaul ◽  
B. Schmidt ◽  
...  
Keyword(s):  
Spin Fluctuations ◽  
Two Dimensional
Sign in / Sign up

Export Citation Format

Share Document