Magnetization plateaux in the classical Shastry-Sutherland lattice

We investigated the classical Shastry-Sutherland lattice under an external magnetic field in order to understand the recently discovered magnetization plateaux in the rare-earth tetraborides compounds RB$_4$. A detailed study of the role of thermal fluctuations was carried out by mean of classical spin waves theory and Monte-Carlo simulations. Magnetization quasi-plateaux were observed at 1/3 of the saturation magnetization at non zero temperature. We showed that the existence of these quasi-plateaux is due to an entropic selection of a particular collinear state. We also obtained a phase diagram that shows the domains of existence of different spin configurations in the magnetic field versus temperature plane.Comment: 4 pages, proceedings of HFM200

Magnetization Process of the Classical Heisenberg Model on the Shastry-Sutherland Lattice

We investigate classical Heisenberg spins on the Shastry-Sutherland lattice and under an external magnetic field. A detailed study is carried out both analytically and numerically by means of classical Monte-Carlo simulations. Magnetization pseudo-plateaux are observed around 1/3 of the saturation magnetization for a range of values of the magnetic couplings. We show that the existence of the pseudo-plateau is due to an entropic selection of a particular collinear state. A phase diagram that shows the domains of existence of those pseudo-plateaux in the $(h, T)$ plane is obtained.Comment: 9 pages, 11 figure

Symbolic capital as a resource of promotion of provincial cities: An analysis of place branding strategies of ural urban destinations

The article analyzes the concept of the symbolic capital of a territory and substantiates the importance of its identification and its use for the promotion of three provincial cities in Russia: Shadrinsk, Chebarkul, and Chelyabinsk. Based on the approach of symbolic interactionism and the use of semiotic analysis, the authors of the article propose to group the resources of the symbolic capital of a territory in three ways. They use signs or symbols, images of the territory, and archetypes. The capital of a provincial city can be perceived symbolically both by external (investors and tourists) and internal (local residents) audiences. They serve as a means of shaping the image and reputation of the place. Both P. Bourdieu’s concept of symbolic capital and V. Radaev’s classification for different types of capital allow us to give examples of conversion from the cultural resources of a territory into symbolic capital. The analysis of the communication resonance of a particular mega event (the meteorite fall on the territory of the Southern Urals in 2013) and the study of cultural heritage of the provincial Russian city of Shadrinsk make it possible to identify the actual directions for converting the intangible resources of cities into their symbolic capital. © 2020, FB and Media Group of Estonian Literary Museum. All rights reserved

High-Order Coupled Cluster Method Study of Frustrated and Unfrustrated Quantum Magnets in External Magnetic Fields

We apply the coupled cluster method (CCM) in order to study the ground-state properties of the (unfrustrated) square-lattice and (frustrated) triangular-lattice spin-half Heisenberg antiferromagnets in the presence of external magnetic fields. Here we determine and solve the basic CCM equations by using the localised approximation scheme commonly referred to as the `LSUB$m$' approximation scheme and we carry out high-order calculations by using intensive computational methods. We calculate the ground-state energy, the uniform susceptibility, the total (lattice) magnetisation and the local (sublattice) magnetisations as a function of the magnetic field strength. Our results for the lattice magnetisation of the square-lattice case compare well to those results of QMC for all values of the applied external magnetic field. We find a value for magnetic susceptibility of $\chi=0.070$ for the square-lattice antiferromagnet, which is also in agreement with the results of other approximate methods (e.g., $\chi=0.0669$ via QMC). Our estimate for the range of the extent of the ($M/M_s=$)$\frac 13$ magnetisation plateau for the triangular-lattice antiferromagnet is $1.37< \lambda < 2.15$, which is in good agreement with results of spin-wave theory ($1.248 < \lambda < 2.145$) and exact diagonalisations ($1.38 < \lambda < 2.16$). The CCM value for the in-plane magnetic susceptibility per site is $\chi=0.065$, which is below the result of the spin-wave theory (evaluated to order 1/S) of $\chi_{SWT}=0.0794$.Comment: 30 pages, 13 figures, 1 Tabl

Hubbard ladders in a magnetic field

The behavior of a two leg Hubbard ladder in the presence of a magnetic field is studied by means of Abelian bosonization. We predict the appearance of a new (doping dependent) plateau in the magnetization curve of a doped 2-leg spin ladder in a wide range of couplings. We also discuss the extension to N-leg Hubbard ladders

Coupled Ising models with disorder

In this paper we study the phase diagram of two Ising planes coupled by a standard spin-spin interaction with bond randomness in each plane. The whole phase diagram is analyzed by help of Monte Carlo simulations and field theory arguments.Comment: 9 pages and 3 figure

Magnetization plateaux in the classical shastry-sutherland lattice

We investigated the classical Shastry-Sutherland lattice under an external magnetic field in order to understand the recently discovered magnetization plateaux in the rare-earth tetraborides compounds RB4. A detailed study of the role of thermal fluctuations was carried out by mean of classical spin waves theory and Monte-Carlo simulations. Magnetization quasi- plateaux were observed at 1=3 of the saturation magnetization at non zero temperature. We showed that the existence of these quasi-plateaux is due to an entropic selection of a particular collinear state. We also obtained a phase diagram that shows the domains of existence of different spin configurations in the magnetic field versus temperature plane.Departamento de Físic