scholarly journals Topological Transition Points in a Magnetic-Semiconductor Periodic Structure in an External Magnetic Field

2019 ◽  
Vol 135 (4) ◽  
pp. 626-631 ◽  
Author(s):  
I. Fedorin ◽  
V. Fesenko ◽  
V. Tuz ◽  
G. Khrypunov ◽  
A. Khrypunova
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Periodic Structure ◽  
Magnetic Semiconductor ◽  
Topological Transition ◽  
Transition Points

scholarly journals Crossing and anti-crossing effects of polaritons in a magnetic-semiconductor superlattice influenced by an external magnetic field

2017 ◽  
Vol 103 ◽  
pp. 285-294 ◽  
Author(s):  
Vladimir R. Tuz ◽  
Volodymyr I. Fesenko ◽  
Illia V. Fedorin ◽  
Hong-Bo Sun ◽  
Valeriy M. Shulga
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Semiconductor ◽  
Semiconductor Superlattice

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.

Frustrations and Phase Transitions in Low-Dimensional Magnetic Systems

2016 ◽  
Vol 845 ◽  
pp. 111-116 ◽  
Author(s):  
Felix Kassan-Ogly ◽  
Alexey I. Proshkin ◽  
Akai K. Murtazaev ◽  
Albert Babaev ◽  
Magomedsheykh Ramazanov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Specific Heat ◽  
Nearest Neighbor ◽  
Exchange Interactions ◽  
Magnetic Systems ◽  
Magnetic Parameters ◽  
1D Chain ◽  
Transition Points ◽  
Low Dimensional

We studied magnetic orderings and frustrations on 1D chain and 2D lattices: square, triangular, kagome, and hexagonal in the Ising, 3-state Potts and standard 4-state Potts models. The spins interrelate with one another via the nearest-neighbor, the next-nearest-neighbor or the third-neighbor exchange interactions and by an external magnetic field. For problem solving we mainly calculated the entropy and specific heat using the rigorous analytical solutions for maximum eigenvalue of Kramers-Wannier transfer-matrix and exploiting computer simulation, par excellence, by Wang-Landau algorithm. Whether a system is ordered or frustrated is related to 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 topology of a lattice.

Terahertz emission characteristics of GaMnAs dilute magnetic semiconductor under 650 mT external magnetic field

2017 ◽  
Vol 17 (4) ◽  
pp. 522-526 ◽  
Author(s):  
Alexander De Los Reyes ◽  
Elizabeth Ann Prieto ◽  
Karim Omambac ◽  
Jeremy Porquez ◽  
Lorenzo Lopez ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Dilute Magnetic Semiconductor ◽  
Magnetic Semiconductor ◽  
Emission Characteristics ◽  
Terahertz Emission

scholarly journals Spin Flows in Magnetic Semiconductor/Insulator/Superconductor Tunneling Junction

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Michihide Kitamura ◽  
Akinobu Irie
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Band Structure ◽  
Magnetic Semiconductor ◽  
Tunneling Junction ◽  
External Voltage ◽  
Switching Device ◽  
Band Structure Calculations ◽  
Minority Spin ◽  
Structure Calculations

Tunneling currents along the c-axis of the majority and minority spin electrons have been studied for a magnetic semiconductor (MS)/insulator (I)/superconductor (S) tunneling junction consisting of a Ga1−xMnxAs MS with x = 1/32, a nonmagnetic I with a realistic dimension, and a HgBa2Ca2Cu3O8.4 (Hg-1223) high-Tc S. The normalized charge and spin currents, QT,Cμ′Vex and QT,Sμ′Vex, and the flows of the majority ↑ and minority ↓ spin electrons, QT,↑μ′Vex and QT,↓μ′Vex, have been calculated at a fixed external voltage Vex, as a function of the magnetic moment μ′  (≡μ/μB) per a Mn atom which is deduced from the band structure calculations. It is found that the tunneling due to the minority spin electron dominates when μ′<2.4, but such a phenomenon is not found for μ′>2.4. We have pointed out that the present MS/I/S tunneling junction seems to work as a switching device in which the ↑ and ↓ spin flows can be easily controlled by the external magnetic field.

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