Applications Of Ferroelectrics

Temperature Dependence of the Dielectric Constant Calculated Using a Mean Field Model Close to the Smectic A - Isotropic Liquid Transition

“…Again, a very large value of ≈14 for the racemic A7 also indicates a first order SmA-I transition in this compound in comparison to the value of 1 / 2  for the 50% mixture which can be considered to exhibit a second order SmA-I transition within the temperature intervals studied. This slope ratio can be used as a criterion to describe a first or second order transition exhibited by the ferroelectric liquid crystals, which was used in particular for the smectic A-smectic C* (AC*) phase transition in A7 (Bahr et al, 1987), and also in general for the ferroelectrics and related materials (Lines & Glass, 1979). The dielectric constant ε ⊥ was calculated using the temperature dependence of the orientational order parameter ψ (Eq.19) from the mean field theory in Eq.…”

Microstructural and Electrical Study of (BA0.6 SR0.4)(ZR1-X Tix)o3 Ceramics

“…Since the discovery of ferroelectric properties in BaTiO 3 , a large number of ferroelectrics with the perovskite structure having a general formula ABO 3 perovskite has extensively been studied in search for new materials for device applications [1][2]. The growing interest in search of suitable materials for device has led to the development of large number of complex ferroelectric ceramics with a wide variety of composition and stable structure.…”

Collective phase-like mode and the role of lattice distortions atTN∼TCin RMn2O5(R= Pr, Sm, Gd, Tb, Bi)

“…[7] Although, the phase transition may be broadly considered as displacive or order-disorder more recent local structure studies suggest that real compounds share in different degrees properties belonging to both limits [8] A characteristic hysteresis loop develops in the ferroelectric state under an external electric field that mimics the magnetic susceptibility behavior in magnetic ordered systems. [7] Materials with simultaneous occurrence of electric and magnetic order are called multiferroics. They have two order parameters, spontaneous polarization (antiferroelectric, ferroelectric, ferrielectric), and spontaneous magnetization (antiferromagnetism, ferromagnetism, ferrimagnetism) triggering, by magnetoelectric coupling, one order by the other.…”