Enhanced dielectric and piezoelectric properties of Ta-doped 0.50(Na0.5Bi0.5)TiO3–0.50(K0.5Bi0.5)TiO3 lead-free ferroelectric ceramics

Synthesis of 0.64Pb(Mg1/3Nb2/3)O3–0.36PbTiO3 ceramic near morphotropic phase boundary for high performance piezoelectric, ferroelectric and pyroelectric applications

“…A material that shows a diffused phase transition (broad peak) deviates strongly from Curie-Weiss law. The degree of diffuseness for any material can be calculated by using the modified Curie Weiss law [26] as given in Eq. (2),…”

Domain switching contribution to the ferroelectric, fatigue and piezoelectric properties of lead-free Bi0.5(Na0.85K0.15)0.5TiO3 films

“…6 Because more possible polarization variants are available, the ferroelectric, fatigue and piezoelectric properties are enhanced at morphotropic phase boundary bulk compositions. [7][8][9] Among BNT-based solid solutions, Bi 0.5 Na 0.5 -TiO 3 -Bi 0.5 K 0.5 TiO 3 (BNT-BKT) systems have been received a great deal of attention due to its piezoelectric properties in the rhombohedral-tetragonal morphotropic phase boundary at optimal composition of Bi 0.5 (Na 0.85 K 0.15 ) 0.5 TiO 3 (BKNT15). [10][11][12] With the development of micro-electro-mechanical, lm devices strongly need to be developed.…”

Phase development and dielectric responses in PMNKBT solid solutions

“…, it is observed that the dielectric constant ε slowly decreases with increase in applied frequency f. This can be explained on the basis of oscillation of free dipoles in presence of alternating field. At very low frequencies (f << 1/τ, τ is the relaxation time), dipoles follow the electric field, while at very high frequencies (f >> 1/τ) dipoles begin to lag behind the field and ε slightly decreases 42,44 . It is also reported that the higher values of ε at low frequencies is due to space charge polarization or accumulation of charges at interfaces of sample and electrode 44 .…”

“…At very low frequencies (f << 1/τ, τ is the relaxation time), dipoles follow the electric field, while at very high frequencies (f >> 1/τ) dipoles begin to lag behind the field and ε slightly decreases 42,44 . It is also reported that the higher values of ε at low frequencies is due to space charge polarization or accumulation of charges at interfaces of sample and electrode 44 . From the Figure6,it is observed that the PMN-KBT for x = 0.35 exhibits higher value of ε, while it is moderately high for x = 0.25.…”

“…The values of  and  are both material constants depending on the composition and structure. In a composition with the diffused phase transition such as relaxor ferroelectric, the value of  is expected to be 2 44 . For γ = 1, the system behaves as a normal ferroelectric system, while for γ = 2 it depicts a relaxor system 45 .…”