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The influence of a non-perfect surface on the critical properties of magnetic spin-1/2 Ising film on a cubic lattice structure is studied using Monte Carlo simulations based on Metropolis algorithm. The surface magnetization and the surface effective exponent have been studied for several concentration p. Far from the critical temperature, the surface effective exponent βeffs decreases with increasing the concentration p. [ABSTRACT FROM AUTHOR]

Using Monte Carlo simulation with the Metropolis algorithm, we have studied the critical behaviour of magnetic spin 1/2 Ising film on a cubic lattice structure. We drive the effective exponent of the each layer βeff(z,t) and of the film βefff (t) as a function of reduced temperature t. A particular attention is paid for the evaluation of the variation of the critical exponents with the film thickness. [ABSTRACT FROM AUTHOR]

The multi-component Ising-like network model on x-y rectangular lattice was developed to describe the ferroelectric phase transition in Tetragonal Tungsten Bronze (TTB) compounds. Using Monte Carlo simulation with Metropolis algorithm we reproduced the phase diagram of this model as a function of the temperature and exchange interaction and demonstrated it coherence with experimental data. [ABSTRACT FROM AUTHOR]

Glass-ceramics in the system xBaTiO3-(1-x)NaPO3 (0 ≤ x ≤ 14, x in mol%) have been prepared and characterized. The structural organization of the glass-ceramics has been studied using XRD diffraction and infra-red (FTIR), 31P Magic angle spinning (MAS-NMR) and dielectric spectroscopies. Results suggest two distinct regions comprising the glass structure, one with low-BaTiO3 content and the other with higher content of the ferroelectric compound BaTiO3. The depolymerisation effects and the structure changes, promoted by BaTiO3 addition, are evidenced by means of the IR and NMR results. Dielectric permittivity shows that the ferroelectric-paraelectric transition temperature of each glass-ceramic appears at the same temperature for a pure BaTiO3 ceramic. [ABSTRACT FROM AUTHOR]

Samples of zelliges, from the Dar-El Beïda Palace built in Meknes (Morocco) in the 18th century, were studied by optical absorption and Raman spectroscopies. The results obtained by the two techniques were in agreement and show that the glazes of the zelliges are lead oxide-rich in composition. Other phases were also detected, mainly the SnO2 cassiterite opacifier for the white glaze, and heamatite (α-Fe2O3) in association with magnetite Fe3O4 and manganese oxide (MnO2) for the brown glaze. For the blue and green glazes, the elements responsible for the coloring are cobalt (Co2+) and copper (Cu2+), respectively. [ABSTRACT FROM AUTHOR]