scholarly journals Magnetic properties of two-dimensional nanodots: Ground state and phase transition

AIP Advances ◽  
2013 ◽  
Vol 3 (12) ◽  
pp. 122121 ◽  
Author(s):  
Maciej Kasperski ◽  
Henryk Puszkarski ◽  
Danh-Tai Hoang ◽  
H. T. Diep
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Ground State ◽  
Two Dimensional

Strain-driven Phase Transition and Spin Polarization of Re-doped Transition-Metal Dichalcogenides

2021 ◽  
Author(s):  
Ruining Wang ◽  
Chen-Dong Jin ◽  
Hu Zhang ◽  
Ru-Qian Lian ◽  
Xingqiang Shi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Transition Metal ◽  
Spin Polarization ◽  
Transition Metal Dichalcogenides ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Two Dimensional ◽  
Energy Landscapes ◽  
Metal Dichalcogenides

Two-dimensional transition metal dichalcogenides (TMDCs) are promising in spintronics due to their spin-orbit coupling, but the intrinsic non-magnetic properties limit their further developments. Here, we focus on the energy landscapes...

scholarly journals Exploration of magnetism in 3D and 2D systems

2019 ◽  
Author(s):  
◽  
Ashutosh Dahal
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Low Temperature ◽  
Data Storage ◽  
Measurement Techniques ◽  
Honeycomb Lattice ◽  
Synthesis Methods ◽  
Detailed Knowledge ◽  
Two Dimensional ◽  
Magnetic Fluctuations

Magnetism has intruded in every aspect of our life, from electric motors to hard disk data storage to space technologies. Developing strong understanding of underlying magnetic properties is of utmost importance to reach new frontiers of technological advancement. During my Ph.D. research, I have explored complementary research venues in three dimensional as well as two dimensional materials to understand basic magnetic properties that were either not known or explored for the first time. In this quest, I have studied three different physical systems with overlapping structural and/or magnetic and electrical properties: nickel monosilicides (NiSi), cobalt-doped calcium ruthenate (Ca(CoxRu1-x)O3) and europium manganese arsenide (EuMn2As2). One of the key aspects of my research is to understand how magnetic moments correlate with each other. Understanding this fundamental question can help us in elucidating the mechanism behind novel magnetic proper-ties manifested by the above mentioned materials. While NiSi is found to manifest a new phenomenon of magnetism driven intermediate metallic-superconducting phase, (Ca(CoxRu1-x)O3) tends to exhibit the metal-insulator transition with the critical phase boundary coinciding with the onset of strong continuum type magnetic fluctuations. Despite the presence of strong dynamic magnetic moment correlation, no trace of any type of static magnetic order is detected in any of these materials. On the other hand, strong static order with two consecutive antiferromagnetic phase transitions are detected in the intertwined honeycomb structured EuMn2As2. During the process of studying bulk materials using macroscopic measurement techniques, I have acquired detailed knowledge of chemical synthesis methods and several experimental measurement techniques, including the analysis of magnetic susceptibility and neutron scattering methods. The gained knowledge is applied in pinpointing the low temperature magnetic phase transition in an ongoing project in the lab of two dimensional artificial magnetic (permalloy) honeycomb lattice. Two dimensional magnetic honeycomb lattice provides a unique platform to study emergent magnetic phenomena in reduced degrees of freedom. The system is expected to develop novel spin solid order at low temperature. I have performed detailed analysis of non-linear susceptibility of permalloy honeycomb lattice, which revealed the non-thermodynamic nature of phase transition to the spin solid state in this system. In the ensuing chapters, I have explained each project in great detail. A brief overview of the previous research works and the motivations behind the study is provided in the Introduction section.

Possible ferromagnetism of dense quark matter

2018 ◽  
Vol 96 (11) ◽  
pp. 1163-1172
Author(s):  
Kausik Pal
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Single Particle ◽  
Ground State ◽  
Quark Matter ◽  
State Energy ◽  
Magnetic Instability ◽  
Dense Quark Matter ◽  
Spin Polarized

The cardinal focus of the present review is to investigate the possibility of the para-ferro phase transition of dense quark matter. For these, the calculation of the single-particle energies, ground state energy (GSE) densities, and spin susceptibility χ of degenerate quark matter with one gluon exchange interaction in terms of spin-dependent Landau parameters (LPs) have been presented. The expressions for the GSE and χ of cold and dense spin-polarized quark matter have been derived with corrections due to correlation. Furthermore, the magnetic properties of spin polarized quark matter have been discussed by evaluating the magnetization ⟨M⟩ and magnetic susceptibility χM in terms of LPs. Finally, the possibility of magnetic instability has been revealed by studying the density dependence of ⟨M⟩ and χM.

scholarly journals Non-collinear ground state and stable bimerons from four-spin chiral interactions in D3h magnet

2021 ◽  
Vol 2015 (1) ◽  
pp. 012118
Author(s):  
G R Rakhmanova ◽  
A N Osipov ◽  
D I Ilin ◽  
I V Shushakova ◽  
I V Iorsh
Keyword(s):  
Phase Transition ◽  
Ground State ◽  
Magnetic Order ◽  
Point Group ◽  
Exchange Interactions ◽  
Two Dimensional ◽  
Magnetic Ground State ◽  
Magnetic Vortices ◽  
Spin Interactions ◽  
Magnetic Skyrmions

Abstract We demonstrate that four-spin interactions in crystals with D3h point group of symmetry can cause a phase transition from a collinear state to a non-collinear magnetic ground state (such as magnetic vortices or magnetic skyrmions), while all anti-symmetric chiral terms are forbidden by symmetry in such crystals. Moreover, D3h point group rather common among two dimensional magnets. Taking into account possible four-spin chiral exchange interactions is important for understanding noncollinear magnetic order in these systems. We also address a possible stabilization of bimerons by the same contribution.

scholarly journals Phase transition and monopole densities in a nearest neighbor two-dimensional spin ice model

2017 ◽  
Vol 31 (31) ◽  
pp. 1750237
Author(s):  
C. W. Morais ◽  
D. N. De Freitas ◽  
A. L. Mota ◽  
E. C. Bastone
Keyword(s):  
Phase Transition ◽  
Long Range ◽  
Ground State ◽  
Nearest Neighbor ◽  
Nearest Neighbors ◽  
Dipolar Interaction ◽  
Effective Model ◽  
Two Dimensional ◽  
Spin Ice ◽  
Ice Model

In this work, we show that, due to the alternating orientation of the spins in the ground state of the artificial square spin ice, the influence of a set of spins at a certain distance of a reference spin decreases faster than the expected result for the long range dipolar interaction, justifying the use of the nearest neighbor two-dimensional square spin ice model as an effective model. Using an extension of the model presented in Y. L. Xie et al., Sci. Rep. 5, 15875 (2015), considering the influence of the eight nearest neighbors of each spin on the lattice, we analyze the thermodynamics of the model and study the dependence of monopoles and string densities as a function of the temperature.

Bifurcation Research Two-Dimensional XYX Quantum Model Based on Fidelity

2014 ◽  
Vol 543-547 ◽  
pp. 1764-1768
Author(s):  
Sheng Hao Li ◽  
Xiao Bing Wu ◽  
Chong Fu Huang ◽  
Hong Lei Wang
Keyword(s):  
Phase Transition ◽  
Ground State ◽  
Multibody System ◽  
Quantum Model ◽  
Two Dimensional ◽  
Initial State ◽  
State Evolution ◽  
Quantum Critical Phenomena ◽  
Reduced Density ◽  
Bifurcation Behavior

For two-dimensional XYX quantum model, iPEPS algorithm can select randomly initial state evolution, and get two degenerate symmetric broken ground state wave functions. In the quantum model, not only bifurcation behavior of ground state fidelity can be used, but bifurcation behavior of reduced density matrix fidelity can also be used to determine the phase transition point and its type caused by spontaneous broken symmetry of quantum of the system. Therefore, spontaneous symmetry breaking based on fidelity bifurcation can determine quantum phase transition one quantum system had gone through. This nature provides a method to further study quantum critical phenomena in quantum multibody system

CRITICAL COARSENING DYNAMICS OF SPIN S =1/2, 3/2 ANTIFERROMAGNETIC ISING MODEL ON TRIANGULAR LATTICE

2006 ◽  
Vol 17 (04) ◽  
pp. 591-600
Author(s):  
KWANGHOON CHUNG ◽  
MOOKYUNG CHEON ◽  
IKSOO CHANG
Keyword(s):  
Phase Transition ◽  
Ising Model ◽  
Triangular Lattice ◽  
Ground State ◽  
Finite Temperature ◽  
Xy Model ◽  
Two Dimensional ◽  
Type Phase ◽  
Coarsening Dynamics ◽  
Antiferromagnetic Ising Model

The critical coarsening dynamics of the spin S =1/2, 3/2 antiferromagnetic Ising model on a triangular lattice is studied by the dynamic Monte Carlo simulation using a heat bath algorithm. The triangular antiferromagnetic Ising (TAI) model possesses an intrinsic geometrical frustration and a large degeneracy of ground state which may affect the equilibrium and non-equilibrium critical behaviors. The S =1/2 TAI has no phase transition at a finite temperature, but it was suggested that the S =3/2 TAI has the Kosterlitz–Thouless (KT)-type phase transition at a finite temperature. We employ a finite size scaling approach for the correlation function from the short-time dynamics of the S =1/2, 3/2 TAI to calculate the values of the static critical exponent η and the dynamic exponent z. For the S =1/2 TAI, our dynamic scaling analysis provides η =0.498±0.006 and z =2.278±0.020 at T =0, agreeing with the previous results. For the S =3/2 TAI, after identifying a KT-transition temperature TKT =0.51±0.01, we find the temperature-dependent η ranging from 0.301±0.008 at T =0.51 to 0.224±0.016 at T =0 along the KT-line whereas the value of z =2.20±0.06 is constant for T≤TKT. It is shown that the spin S =3/2 TAI model and the two-dimensional XY model, sharing the KT-type phase transition, exhibit similar static critical and coarsening dynamics behavior. For both the S =1/2, 3/2 TAI, the value of z (η) is compatible with (larger than) that of the Ising model at Tc and the XY model for T≤TKT in two-dimension. Our results imply that although the quasi-long-range order disappears with ηXY =0 in the two-dimensional XY model at T =0, the S =3/2 TAI still maintains it with η TAI =0.224 due to the effect of a frustration and a high degeneracy of ground state.

Magnetic Properties of Diaquabis(phenoxyacetato)manganese(II) and Related Complexes

1984 ◽  
Vol 39 (4) ◽  
pp. 371-375 ◽  
Author(s):  
Tetsuo Asaji ◽  
Kazumasa Aoki ◽  
Daiyu Nakamura
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Temperature Region ◽  
Magnetic Phase ◽  
Two Dimensional ◽  
Ferromagnetic Interaction ◽  
Magnetic Susceptibilities ◽  
Sharp Maximum ◽  
Ordered State

The magnetic susceptibilities of diaquabis(phenoxyacetato)manganese(II), diaquabis(p-chlorophenoxyacetato) manganese(II), and diaquabis(phenoxyacetato)cobalt(II) were determined in a temperature region below 77 K. The temperature dependence of the magnetic susceptibility observed for the first two manganese(II) complexes shows a broad maximum near 2 K. which can be interpreted as arising from two-dimensional Heisenberg antiferromagnets with S = 5/2. The magnetic susceptibility of the cobalt(II) complex obeys the Curie-Weiss law showing the presence of a ferromagnetic interaction between neighboring cobalt(II) ions. For diaquabis( phenoxyacetato)manganese(II), a magnetic phase transition from a disordered to an antiferromagnetic ordered state was located at 1.633 ± 0.005 K from the sharp maximum of the magnetic susceptibility.

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