Internal friction in ferroelectrics due to interaction of domain boundaries and point defects

Chen

Applied Physics Letters

et al. 2006

105

Acceptor doping and donor doping have been known to result in opposite ferroelectric aging effects, but the aging effect of hybrid-doped (acceptor+donor) ferroelectrics has remained unclear. In this letter the authors report the aging effect in Mn3++Nb5+ hybrid-doped BaTiO3 ceramics with acceptor fixed at 1mol% but with donor varied from 0.5to2mol%. The authors found surprisingly that ferroelectric aging existed in all the samples, no matter which of the two, acceptor or donor, was dominant: all the samples showed a double hysteresis loop after aging, but with increasing donor (Nb5+) concentration the coercive field and hysteresis decrease. Meanwhile, a large nonlinear recoverable electrostrain up to 0.17% (due to reversible domain switching) was observed at 3kV∕mm, which exceeded that of acceptor-monodoped ceramics and was about twice the piezoelectric strain of hard lead zirconate titanate. These results demonstrate that hybrid doping is an effective way to enhance the domain-switching-related electrostrain properties. Finally, the aging effect of hybrid-doped ferroelectrics was explained.

mentioning

confidence: 99%

Ferroelectric aging effect in hybrid-doped BaTiO3 ceramics and the associated large recoverable electrostrain

Chen

Applied Physics Letters

et al. 2006

105

“…A sample doped with Nb has also shown the same pattern of elastic softening [110]. Characteristic peaks in acoustic loss, expressed in terms of the inverse mechanical quality factor, Q À1 , show dispersion with respect to frequency and are attributed to the motion under stress of the ferroelastic twin walls [106,107,109,111]. From the measurements of Bourim et al [107] at Hz frequencies, it appears that the twin walls become pinned by oxygen vacancies in the vicinity of *400 K, below which the loss returns to low values.…”

Section: Strain and Elasticitymentioning

confidence: 88%

Elastic and anelastic relaxation behaviour of perovskite multiferroics I: PbZr0.53Ti0.47O3 (PZT)–PbFe0.5Nb0.5O3 (PFN)

et al. 2016

Perovskites in the ternary system PbTiO 3 (PT)-PbZrO 3 (PZ)-Pb(Fe 0.5 Nb 0.5 )O 3 (PFN) have attracted close interest because they can display simultaneous ferroelectric, magnetic and ferroelastic properties. Those with the most sensitive response to external fields are likely to have compositions near the morphotropic phase boundary (MPB) which lies close to the binary join Pb(Zr 0.53 Ti 0.47 )O 3 (PZT)-PFN. In the present study, the strength and dynamics of strain coupling behaviour which accompanies the development of ferroelectricity and (anti)ferromagnetism in ceramic PZT-PFN samples have been investigated by resonant ultrasound spectroscopy. Elastic softening ahead of the cubic-tetragonal transition does not fit with models based on dispersion of the soft mode or relaxor characteristics but is attributed, instead, to coupling between acoustic modes and a central peak mode from correlated relaxations and/or microstructure dynamics. Softening of the shear modulus through the transition by up to *50 % fits with the expected pattern for linear/quadratic strain/order parameter coupling at an improper ferroelastic transition and close to tricritical evolution for the order parameter. Superattenuation of acoustic resonances in a temperature interval of *100 K below the transition point is indicative of mobile ferroelastic twin walls. By way of contrast, the first-order tetragonalmonoclinic transition involves only a small change in the shear modulus and is not accompanied by significant changes in acoustic dissipation. The dominant Address correspondence to E-mail: mc43@esc.cam.ac.uk DOI 10.1007/s10853-016-0280-2 J Mater Sci (2016) 51:10727-10760 feature of the elastic and anelastic properties at low temperatures is a concaveup variation of the shear modulus and relatively high loss down to the lowest temperature, which appears to be the signature of materials with substantial local strain heterogeneity and a spectrum of strain relaxation times. No evidence of magnetoelastic coupling has been found, in spite of the samples displaying ferromagnetism below *550 K and possible spin glass ordering below *50 K. For the important multiferroic perovskite ceramics with compositions close to the MPB of ternary PT-PZ-PFN, there must be some focus in future on the role of strain heterogeneity.

“…• ) [13]. The activation parameters of the P R2 peak (H = 2.35 eV, τ 0 = 1.55 × 10 −24 ) obtained suggests that the P R2 peak may be connected with a more complex process.…”

Section: Resultsmentioning

confidence: 99%

Modified PZT ceramics as a material that can be used in micromechatronics

Zachariasz

Bochenek

2015

Eur. Phys. J. B

Abstract.Results on investigations of the PZT type ceramics with the following chemical composition: Pb0.94Sr0.06(Zr0.50Ti0.50)0.99Cr0.01O3 (PSZTC) which belongs to a group of multicomponent ceramic materials obtained on basis of the PZT type solid solution, are presented in this work. Ceramics PSZTC was obtained by a free sintering method under the following conditions: Tsint = 1250• C and tsint = 2 h. Ceramic compacts of specimens for the sintering process were made from the ceramic mass consisting of a mixture of the synthesized PSZTC powder and 3% polyvinyl alcohol while wet. The PSZTC ceramic specimens were subjected to poling by two methods: low temperature and high temperature. On the basis of the examinations made it has been found that the ceramics obtained belongs to ferroelectric-hard materials and that is why it may be used to build resonators, filters and ultrasonic transducers.