The effect of the surface field on the phase diagrams of a transverse Ising thin film

Within an effective field theory (EFT), the phase diagrams of a transverse Ising thin film (TIM) has been investigated. The effects of the Ωs on the critical temperature are discussed by including the modification of surface exchange interaction. The phase diagrams are also determinated as function of the transverse field for different values of the film thickness n and for same value of ∆sWithin an effective field theory (EFT), the phase diagrams of a transverse Ising thin film (TIM) has been investigated. The effects of the Ωs on the critical temperature are discussed by including the modification of surface exchange interaction. The phase diagrams are also determinated as function of the transverse field for different values of the film thickness n and for same value of ∆

Ising-Like Model For Ferroelectric Phase Transitions In Tetragonal Tungsten Bronze Compounds

The two-component anisotropic Ising-like model was proposed to model the ferroelectric phase transitions in Tetragonal Tungsten Bronze (TTB) compounds. Using the mean-field approach we reconstructed the phase diagram of the TTB system and showed that depending on he relative strength of the interaction parameters there ferroelectric states are possible: (i) the state with y-directed polarization that corresponds to the tetragonal ferroelectric phase in TTB compounds, (ii) the state with x-directed polarization that corresponds to the orthorhombic TTB phase and (iii)  the state with superposition of x- and y- polarization components that can correspond to the not yet discovered mixed phase.The two-component anisotropic Ising-like model was proposed to model the ferroelectric phase transitions in Tetragonal Tungsten Bronze (TTB) compounds. Using the mean-field approach we reconstructed the phase diagram of the TTB system and showed that depending on he relative strength of the interaction parameters there ferroelectric states are possible: (i) the state with y-directed polarization that corresponds to the tetragonal ferroelectric phase in TTB compounds, (ii) the state with x-directed polarization that corresponds to the orthorhombic TTB phase and (iii)  the state with superposition of x- and y- polarization components that can correspond to the not yet discovered mixed phase

Phase diagrams of ferroelectric thin film with two surface layers

Phase diagram of a ferroelectric thin film with two surface layers is studied in frame of the effective field theory (EFT) of transverse Ising model (TIM). The surface of the system is formed from two layers characterized by the exchange interaction anisotropy $R_s =\frac{J_s }{J}$ and the transverse field $\Omega _{s}$. The crossover from the ferroelectric phase (FP) to the paraelectric phase (PP) is discussed. The phase diagram of the system is studied in$\big( {\frac{K_B T_c }{J},\frac{\Omega _s }{J}} \big)$ coordinates as function of the thickness parameter L. The special attention is given to the effect of the transverse field $\Omega _{s}$ on the phase transitions