Solitons in a classical inhomogeneous ferromagnetic chain with nearest- and next-nearest-neighbor exchange interactions

2019 ◽  
Author(s):  
R. S. Kamburova ◽  
S. K. Varbev ◽  
M. T. Primatarowa
Keyword(s):  
Nearest Neighbor ◽  
Exchange Interactions ◽  
Ferromagnetic Chain

Loss of classicality in the alternating spin-½/spin-1 chain, in the presence of next-neighbor couplings and Dzyaloshinskii-Moriya interactions

2022 ◽  
Author(s):  
Abhiroop Lahiri ◽  
Swapan K Pati
Keyword(s):  
Ground State ◽  
Nearest Neighbor ◽  
Spiral Structure ◽  
Exchange Interactions ◽  
Quantum Fluctuations ◽  
Wave Theory ◽  
Range Order ◽  
Density Matrix Renormalization Group ◽  
Density Matrix Renormalization ◽  
Spin Spiral

Abstract We have considered and alternating spin-½/spin-1 chain with nearest-neighbor (J1), next-nearest neighbor (J2) antiferromagnetic Heisenberg interactions along with z-component of the Dzyaloshinskii-Moriya(DM) (Dz) interaction. The Hamiltonian has been studied using (a) Linear Spin-Wave Theory(LSWT) and (b) Density Matrix Renormalization Group (DMRG). The system had been reported earlier as a classical ferrimagnet only when nearest neighbor exchange interactions are present. Both the antiferromagnetic next-nearest neighbor interactions and DM interactions introduce strong quantum fluctuations and due to which all the signatures of ferrimagnetism vanishes. We find that the nonzero J2 introduces strong quantum fluctuations in each of the spin sites due to which the z-components of both spin-1 and spin-1/2 sites average out to be zero. The ground state becomes a singlet. The presence of J1 along with Dzintroduces a short range order but develops long range order along the XY plane. J1 along with J2induces competing phases with structure factor showing sharp and wide peaks, at two different angles reflecting the spin spiral structure locally as well as in the underlying lattice. Interestingly, we find that the Dz term removes the local spin spiral structure in z-direction, while developing a spiral order in the XY plane.

scholarly journals Frustrations and phase transitions in magnets of various dimensionality

2018 ◽  
Vol 185 ◽  
pp. 11002
Author(s):  
Felix Kassan-Ogly ◽  
Alexey Proshkin
Keyword(s):  
Magnetic Field ◽  
Phase Transitions ◽  
External Magnetic Field ◽  
Specific Heat ◽  
Nearest Neighbor ◽  
Linear Chain ◽  
Exchange Interactions ◽  
Specific Model ◽  
Main Challenge ◽  
Transition Points

We studied magnetic orderings, phase transitions, and frustrations in the Ising, 3-state Potts and standard 4-state Potts models on 1D, 2D, and 3D lattices: linear chain, square, triangular, kagome, honeycomb, and body-centered cubic. The main challenge was to find out the causes of frustrations phenomena and those features that distinguish frustrated system from not frustrated ones. The spins may interrelate with one another via the nearest-neighbor, the next-nearest-neighbor or higher-neighbor exchange interactions and via an external magnetic field that may be either competing or not. For problem solving we mainly calculated the entropy and specific heat using the rigorous analytical solutions for Kramers-Wannier transfer-matrix and exploiting computer simulation, par excellence, by Wang-Landau algorithm. Whether a system is ordered or frustrated is depend on the signs and values of exchange interactions. An external magnetic field may both favor the ordering of a system and create frustrations. With the help of calculations of the entropy, the specific heat and magnetic parameters, we obtained the points and ranges of frustrations, the frustration fields and the phase transition points. The results obtained also show that the same exchange interactions my either be competing or noncompeting which depends on the specific model and the lattice topology.

scholarly journals Magnet with Ferromagnetic Nearest-Neighbor and Antiferromagnetic Next-Nearest-Neighbor Exchange Interactions

2009 ◽  
Vol 115 (5) ◽  
pp. 925-930 ◽  
Author(s):  
R. Szymczak ◽  
H. Szymczak ◽  
G. Kamieniarz ◽  
G. Szukowski ◽  
K. Jaśniewicz-Pacer ◽  
...  
Keyword(s):  
Nearest Neighbor ◽  
Exchange Interactions

scholarly journals Interplay between spatial anisotropy and next-nearest-neighbor exchange interactions in the triangular Heisenberg model

2020 ◽  
Vol 102 (22) ◽  
Author(s):  
M. G. Gonzalez ◽  
E. A. Ghioldi ◽  
C. J. Gazza ◽  
L. O. Manuel ◽  
A. E. Trumper
Keyword(s):  
Heisenberg Model ◽  
Nearest Neighbor ◽  
Exchange Interactions ◽  
Spatial Anisotropy

THE SPIN-1 BLUME–CAPEL MODEL WITH ALTERNATINGLY CHANGING BILINEAR EXCHANGE INTERACTIONS BETWEEN SUBLATTICES

2012 ◽  
Vol 26 (05) ◽  
pp. 1250031 ◽  
Author(s):  
ERHAN ALBAYRAK
Keyword(s):  
Crystal Field ◽  
Nearest Neighbor ◽  
Bethe Lattice ◽  
Exchange Interactions ◽  
Coordination Numbers ◽  
First Order ◽  
Crystal Fields ◽  
Negative Crystal ◽  
First Order Phase ◽  
Second Order Phase Transition

The spin-1 Blume–Capel model is studied on a Bethe lattice which is divided into two sublattices A and B. Alternatingly changing bilinear exchange interactions, JAB and JBA, between the sublattices, i.e., between the nearest-neighbor shell spins, are assumed. The phase diagrams of the model are studied on the (JAB, T) planes for given values of JBA, crystal fields D and the coordination numbers q = 3, 4 and 6. It was found that the model either displays only second-order phase transition lines at higher crystal field values or second- and first-order phase transitions lines combined at tricritical points at lower negative crystal fields. It was also found that the tricritical points move to higher temperatures and to higher values of JAB as the crystal field becomes more negative.

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