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.

scholarly journals Spin wave theory of a one-dimensional generalized Kitaev model

2020 ◽  
Vol 102 (13) ◽  
Author(s):  
Wang Yang ◽  
Alberto Nocera ◽  
Ian Affleck
Keyword(s):  
Spin Wave ◽  
Wave Theory ◽  
One Dimensional ◽  
Spin Wave Theory ◽  
Kitaev Model

Spin-wave theory of the zero-point energy of solitons in one-dimensional magnets

1989 ◽  
Vol 1 (35) ◽  
pp. 6131-6144
Author(s):  
D H Jones ◽  
Q A Pankhurst ◽  
M F Thomas ◽  
C E Johnson
Keyword(s):  
Spin Wave ◽  
Zero Point ◽  
Wave Theory ◽  
Zero Point Energy ◽  
Point Energy ◽  
One Dimensional ◽  
Spin Wave Theory

Modified spin-wave theory applied to one-dimensional Heisenberg ferromagnet with the nearest-neighbor and next-nearest-neighbor exchange anisotropies

2019 ◽  
Vol 33 (11) ◽  
pp. 1950106
Author(s):  
Yun Liao ◽  
Yuan Chen ◽  
Ji Pei Chen ◽  
Wen An Li
Keyword(s):  
Low Temperature ◽  
Specific Heat ◽  
Spin Wave ◽  
Nearest Neighbor ◽  
Wave Theory ◽  
Heisenberg Ferromagnet ◽  
Thermodynamic Quantities ◽  
One Dimensional ◽  
Spin Wave Theory ◽  
The One

The modified spin-wave theory is used to investigate the one-dimensional Heisenberg ferromagnet with the nearest-neighbor (NN) and next-nearest-neighbor (NNN) exchange anisotropies. The ground-state and low-temperature properties of the system are studied within the self-consistent method. It is found that the effect of the NN anisotropy on the thermodynamic quantities is stronger than that of the NNN anisotropy in the low-temperature region. The anisotropy dependence behaviors (such as the power, exponential and linear laws) are obtained for the position and the height of the maximum of the specific heat and its coefficient, as well as the susceptibility coefficient. The specific heat and its coefficient both display the low-temperature double maxima which are induced by the anisotropies and the NNN interaction. In the very low temperatures the specific heat and the susceptibility behave severally as T[Formula: see text] and T[Formula: see text] at the critical point J2/J1 = −0.25, where J1 and J2 are the NN and NNN interactions, respectively.

scholarly journals Theoretical Models for Magnetic Properties of Iron Pnictides Part II: Boson Formalism

2011 ◽  
Vol 35 (1) ◽  
pp. 45-54 ◽  
Author(s):  
M. Vujinović ◽  
M. Pantić ◽  
M. Pavkov-Hrvojević ◽  
P. Mali
Keyword(s):  
Magnetic Properties ◽  
Spin Wave ◽  
Random Phase ◽  
Wave Theory ◽  
Theoretical Models ◽  
Wave Dispersion ◽  
Iron Pnictides ◽  
Satisfactory Description ◽  
Model Hamiltonian ◽  
Theory And Experiments

Theoretical Models for Magnetic Properties of Iron Pnictides Part II: Boson FormalismWe analyze theJ1-J2-JcHeisenberg model Hamiltonian by using the Dyson-Maleev representation for spin operators and keeping the terms quadratic in Bose operators (linear spin wave theory). From the resulting Hamiltonian we find the ground state magnetisation and spin wave dispersion by employing the Green's function method. We compare the results with those of random phase approximation analysis from Part I and with experimental data for parent pnictide compounds. Neither of the two approaches gives a completely satisfactory description of the magnetic properties of iron pnictides. We conclude that alterations of the model Hamiltonian are needed to get a better agreement between the theory and experiments.

scholarly journals Effects of frustration and cyclic exchange on the spin-1/2 Heisenberg antiferromagnet within the self-consistent spin-wave theory

2016 ◽  
Vol 30 (02) ◽  
pp. 1550251 ◽  
Author(s):  
Milica S. Rutonjski ◽  
Milica V. Pavkov-Hrvojević ◽  
Maja B. Berović
Keyword(s):  
High Temperature ◽  
Spin Wave ◽  
Experimental Studies ◽  
Interlayer Coupling ◽  
Wave Theory ◽  
Wave Dispersion ◽  
The Self ◽  
Spin Wave Theory ◽  
Self Consistent ◽  
Spin Wave Dispersion

The relevance of the quasi-two-dimensional spin-1/2 frustrated quantum antiferromagnet (AFM) due to its possibility of modeling the high-temperature superconducting parent compounds has resulted in numerous theoretical and experimental studies. This paper presents a detailed research of the influence of the varying exchange interactions on the model magnetic properties within the framework of self-consistent spin-wave theory based on Dyson–Maleev (DM) representation. Beside the nearest neighbor (NN) interaction within the plane, the planar frustration up to the third NNs, cyclic interaction and the interlayer coupling are taken into account. The detailed description of the elementary spin excitations, staggered magnetization, spin-wave velocity renormalization factor and ground state energy is given. The results are compared to the predictions of the linear spin-wave theory and when possible also to the second-order perturbative spin-wave expansion results. Finally, having at our disposal improved experimental results for the in-plane spin-wave dispersion in high-[Formula: see text] copper oxide La2CuO4, the self-consistent spin-wave theory (SCSWT) is applied to that compound in order to correct earlier obtained set of exchange parameters and high-temperature spin-wave dispersion.

Spin-waves in CsMnF3

1977 ◽  
Vol 55 (9) ◽  
pp. 773-778 ◽  
Author(s):  
D. Khatamian ◽  
M. F. Collins
Keyword(s):  
Anisotropy Field ◽  
Wave Dispersion ◽  
Exchange Constant ◽  
High Symmetry ◽  
Nearest Neighbour ◽  
Effective Anisotropy ◽  
Neutron Inelastic Scattering ◽  
Dipole Interactions ◽  
Exchange Constants ◽  
Spin Wave Dispersion

The spin-wave dispersion relations were determined by neutron inelastic scattering for the high symmetry directions (0 0 ξ) and (ξ 0 0) in the hexagonal antiferromagnet CsMnF3. The observed data were satisfactorily fitted to a theoretical model with two nearest-neighbour exchange constants, J12 = 0.134 ± 0.003 THz and J23 = 0.094 ± 0.0105 THz, and with one second-nearest-neighbour exchange constant, J35 = −0.0138 ± 0.003 THz. An effective anisotropy field of −2700 ± 900 Oe along the crystal c axis was also included in the model. This field constrains the spins to the basal plane of the crystal and calculations show that magnetic dipole–dipole interactions can account for its observed magnitude.

Sign in / Sign up

Export Citation Format

Share Document