Related papers: Phase transitions in two-dimensional anisotropic q…
The anisotropic XY ferromagnet has been studied by Monte Carlo simulation in a three dimensional simple cubic lattice. The increase in critical temperature (ferro-para transition) has been noticed with increasing the strength of anisotropy.…
Spontaneous symmetry breaking of 2D isotropic Heisenberg magnet is restricted by Mermin-Wagner theorem at any finite temperature in presence of short-range exchange interaction.Kosterlitz and Thouless using XY spin model showed that how an…
We study quantum ferrimagnets in one, two, and three dimensions by using a variety of methods and approximations. These include: (i) a treatment based on the spin coherent state path-integral formulation of quantum ferrimagnets by taking…
Effect of the trimodal random magnetic field distribution on the phase diagrams of the anisotropic quantum Heisenberg model has been investigated for three dimensional lattices with effective field theory (EFT) for a two spin cluster.…
The stranglehold of low temperatures on fascinating quantum phenomena in one-dimensional quantum magnets has been challenged recently by the discovery of anomalous spin transport at high temperatures. Whereas both regimes have been…
The majority of magnetic materials possess some degree of magnetic anisotropy, either at the level of a single ion, or in the exchange interactions between different magnetic ions. Where these exchange interactions are also frustrated, the…
We study the magnetic quantum phase transition in an anisotropic Kondo lattice model. The dynamical competition between the RKKY and Kondo interactions is treated using an extended dynamic mean field theory (EDMFT) appropriate for both the…
The spin-1/2 quantum Heisenberg model is studied in all spatial dimensions d by renormalization-group theory. Strongly asymmetric phase diagrams in temperature and antiferromagnetic bond probability p are obtained in dimensions d \geq 3.…
Magnetic phase transitions between ordered phases are often understood on the basis of semi-classical spin models. Deviations from the classical description due to the quantum nature of the atomic spins as well as quantum fluctuations are…
The thermodynamic properties of a spin S=1/2 tetrameric Heisenberg antiferromagnetic chain with alternating interactions AF1-AF2-AF1-F (AF and F denote the antiferromagnetic and ferromagnetic couplings, respectively) are studied by means of…
In a magnetic field, spin-ladders undergo two zero-temperature phase transitions at the critical fields Hc1 and Hc2. An experimental review of static and dynamical properties of spin-ladders close to these critical points is presented. The…
The Heisenberg antiferromagnet on a two-dimensional triangular lattice is a paradigmatic problem in frustrated magnetism. Even in the classical limit, its properties are far from simple. The "120 degree" ground state favoured by the…
There are some particular one-dimensional models, such as the Ising-Heisenberg spin models with a variety of chain structures, which exhibit unexpected behaviors quite similar to the first and second order phase transition, which could be…
Motivated by theoretical and experimental studies reported by Yamaguchi et al. (Phys. Rev. B 98, 094402 (2018)), we performed a cluster mean-field analysis of an anisotropic Heisenberg model with six competing exchange interactions. We…
The phase diagram of the Heisenberg ferromagnetic model in the presence of a magnetic random field (we have used bimodal distribution) of spin S=1/2 (quantum case) and $S=\infty $ (classical case) on a simple cubic lattice is studied within…
The phase diagram of the uniaxially anisotropic $s=1$ antiferromagnet on the kagom\'e lattice includes a critical line exactly described by the classical three-color model. This line is distinct from the standard geometric classical…
We develop an analytical approach based on a unitary transformation to investigate S=1/2 antiferromagnetic Heisenberg chains coupled to phonons, and find a new quantum phase transition at zero temperature. Although the usual phase…
We have studied the magnetic and thermodynamic properties as well as the NMR spectra of the Heisenberg antiferromagnet RbFe(MoO4)2. The observed temperature dependence of the order parameter, the critical indices and the overall magnetic…
Dynamic behavior of a quantum Heisenberg ferromagnet in the presence of a periodically oscillating magnetic field has been analyzed by means of the effective field theory with two spin cluster. The dynamic equation of motion has been…
In this study, we investigate the magnetic susceptibility, entropy, and isothermal magnetization curve of the spin-1/2 Heisenberg model on an anisotropic triangular lattice using the orthogonalized finite-temperature Lanczos method. In…