Diffuse Phase Transitions and Giant Electrostrictive Coefficients in Lead-Free Fe³⁺-Doped 0.5Ba(Zr_0.2Ti_0.8)O₃-0.5(Ba_0.7Ca_0.3)TiO₃ Ferroelectric Ceramics

Abstract

The electrostrictive effect has some advantages over the piezoelectric effect, including temperature stability and hysteresis-free character. In the present work, we report the diffuse phase transitions and electrostrictive properties in lead-free Fe-doped 0.5Ba(ZrTi)O-0.5(BaCa)TiO (BZT-0.5BCT) ferroelectric ceramics. The doping concentration was set from 0.25 to 2 mol %. It is found that by introducing Fe ion into BZT-0.5BCT, the temperature corresponding to permittivity maximum T was shifted toward lower temperature monotonically by 37 °C per mol % Fe ion. Simultaneously, the phase transitions gradually changed from classical ferroelectric-to-paraelectric phase transitions into diffuse phase transitions with a weak relaxor characteristic. Purely electrostrictive responses with giant electrostrictive coefficient Q between 0.04 and 0.05 m/C are observed from 25 to 100 °C for the compositions doped with 1-2 mol % Fe ion. The Q of Fe-doped BZT-0.5BCT ceramics is almost twice the Q of other ferroelectric ceramics. These observations suggest that the present system can be considered as a potential lead-free material for the applications in electrostrictive area and that BT-based ferroelectric ceramics would have giant electrostrictive coefficient over other ferroelectric systems.

Recent Progress on BaTiO3-Based Piezoelectric Ceramics for Actuator Applications

“…The strain for a 0.5BZT-0.5BCT ceramic can reach 0.05% in an electric field of 500 kV/mm [14], which is even larger than PZT-5H at the same electric field condition. Moreover, Bowman's group and other groups even reported a larger strain level at a near-MPB composition [59][60][61], which makes BZT-BCT ceramic a promising material for actuator application [62][63][64][65]. Besides piezoelectric coefficients, other parameters, such as maximum polarization, remnant polarization, dielectric permittivity etc.…”

Dielectric, electrical conduction and magnetic properties of multiferroic Bi0.8Tb0.1Ba0.1Fe0.9Ti0.1O3 perovskite compound

“…9,10 Processing of BiFeO 3 with other perovskite structured materials, such as BaTiO 3 , would prevent the formation of secondary phases 11,12 and have excellent ferroelectric properties (T C ¼ 120 C). The overall magnetic behaviors of bulk ReFeO 3 are defined as the result of two contributing magnetic \sublattices": (i) an antiferromagnetic oxide lattice in which the spins are coupled via a Fe 3þ -O 2À -Fe 3þ super exchange mechanism; and (ii) a paramagnetic influence from noncoupled ions.…”

Relaxor behaviour and phase transition of perovskite ferroelectrics-type complex oxides (1–x)Na0.5Bi0.5TiO3–xCaTiO3 system

“…Recently, Jin et al [15] reported that the Fe 3+ -doped 0.5Ba(Zr 0.2 Ti 0.8 )O 3 -0.5(Ba 0.7 Ca 0.3 )TiO 3 (BZT-0.5BCT) system shows remarkably high electrostrictive coefficient ( 33 between 0.04 and 0.05 m 4 /C 2 ) and the temperature corresponding to maximum permittivity ( ) shifts towards low temperature by 37 ℃ per 1% of Fe 3+ ions, showing weak relaxor characteristic. Alternatively, a comparable system to (1-x)NBT-xBT is (1-x)BiScO 3 -xPbTiO 3 [16].…”