Phase Diagram of the Square Planar Model with Long Range Isotropic Antiferromagnetic and Dipolar Interactions

2002 ◽  
Vol 189 (2) ◽  
pp. 555-558
Author(s):  
E. Rastelli ◽  
S. Regina ◽  
A. Tassi
2001 ◽  
Vol 15 (21) ◽  
pp. 895-903 ◽  
Author(s):  
M. IFTI ◽  
Q. LI ◽  
C. M. SOUKOULIS ◽  
M. J. VELGAKIS

A two-dimensional Ising model with competing short range ferromagnetic and long range dipolar interactions is used to study the transition properties and phase diagram in ultrathin magnetic films. Monte Carlo simulations in systems with exchange and dipolar interactions reveal a ground state of striped phases with varying width. By raising the temperature, the domain walls are smeared out by fluctuations, leading to a random domain mesoscopic phase with no long-range order, and finally the domains are melted to the high-temperature disordered phase. Local magnetic field distributions and specific heat calculations reproduced transition points consistent with the previous phase diagram of the model. The resemblance to the phase diagram in ultrathin magnetic films, such as in Fe/Cu(100), is discussed.


2015 ◽  
Vol 110 (3) ◽  
pp. 37002 ◽  
Author(s):  
Chen Cheng ◽  
Bin-Bin Mao ◽  
Fu-Zhou Chen ◽  
Hong-Gang Luo

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
E. S. Kozlyakova ◽  
A. V. Moskin ◽  
P. S. Berdonosov ◽  
V. V. Gapontsev ◽  
S. V. Streltsov ◽  
...  

AbstractUniform quasi-one-dimensional integer spin compounds are of interest as a potential realization of the Haldane conjecture of a gapped spin liquid. This phase, however, has to compete with magnetic anisotropy and long-range ordered phases, the implementation of which depends on the ratio of interchain J′ and intrachain J exchange interactions and both uniaxial D and rhombic E single-ion anisotropies. Strontium nickel selenite chloride, Sr2Ni(SeO3)2Cl2, is a spin-1 chain system which passes through a correlations regime at Tmax ~ 12 K to long-range order at TN = 6 K. Under external magnetic field it experiences the sequence of spin-flop at Bc1 = 9.0 T and spin-flip transitions Bc2 = 23.7 T prior to full saturation at Bsat = 31.0 T. Density functional theory provides values of the main exchange interactions and uniaxial anisotropy which corroborate the experimental findings. The values of J′/J = 0.083 and D/J = 0.357 place this compound into a hitherto unoccupied sector of the Sakai-Takahashi phase diagram.


2012 ◽  
Vol 68 (4) ◽  
pp. m404-m404 ◽  
Author(s):  
Andrew R. Burgoyne ◽  
Reinout Meijboom ◽  
Hezron Ogutu

The title compound, [PdCl2{P(C6H11)2(C6H5)}2], forms a monomeric complex with atrans-square-planar geometry. The Pd—P bond lengths are 2.3343 (5) Å, as the Pd atom lies on an inversion centre, while the Pd—Cl bond lengths are 2.3017 (4) Å. The observed structure was found to be closely related to [PdCl2{P(C6H11)3}2] [Grushinet al.(1994).Inorg. Chem.33, 4804–4806], [PdBr2{P(C6H11)3}2] [Clarkeet al.(2003).Dalton Trans.pp. 4393–4394] and [PdCl2P(C6H11)2(C7H7)}2] [Vuotiet al.(2008).Eur. J. Inorg. Chem.pp. 397–407] (C6H11is cyclohexyl and C7H7iso-tolyl). One of the cyclohexyl rings is disordered with the phenyl ring in a 0.587 (9):413 (9) ratio. Five long-range C—H...Cl interactions were observed within the structure.


1978 ◽  
Vol 21 (85) ◽  
pp. 73-83 ◽  
Author(s):  
J. F. Nagle

Abstract Theories of the dielectric constant in ice differ in three fundamentally different ways that are often confused with each other. First, there is the choice of interactions to include in the model, notably whether to try to include long-range dipolar interactions as in the Kirkwood theory or to include only the short-range ice-rule interactions. Second, there is the choice of the kind of statistical quantity calculated, e.g. the Kirkwood correlation factor g or the polarization factor G, which Stillinger and Cotter showed to be different. Finally, there is the choice of the kind of computational tool used, and in original papers this choice often obscures the first two differences. With these distinctions in mind a review is given of current theoretical calculations of the dielectric constant and the residual entropy and how the different theories relate to each other and to experiments.


2018 ◽  
Vol 32 (05) ◽  
pp. 1850053 ◽  
Author(s):  
Ji-Xuan Hou ◽  
Xu-Chen Yu

The long-range interacting spin-1 chain placed in a staggered magnetic field is studied by means of microcanonical approach. Firstly, we study the microcanonical entropy of the system in the thermodynamic limit and find the system is non-ergodic and can exhibit either first-order phase transition or second-order phase transition by shifting the external magnetic field strength. Secondly, we construct the global phase diagram of the system and find a phase transition area in the phase diagram corresponding to the temperature jump of the first-order phase transition.


1991 ◽  
Vol 231 ◽  
Author(s):  
P. Bruno

AbstractTheoretical investigations of the magnetization and Curie temperature of ferromagnetic ultrathin films in the presence of magnetic anisotropy and long-range dipolar interactions are presented. The Curie temperature of fcc (001) cobalt ultrathin films is calculated and compared with experimental results on Co/Cu (001) films. The influence of an external magnetic field, and the surface gradient of the magnetization are also discussed.


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