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The motion of a single planar 180° domain wall was studied in single-crystalline gadolinium molybdate, Gd2(MoO4)3. The switching current and the instantaneous wall positions were recorded using polarized light in an optical microscope and subsequent image processing. A pronounced deaging (wake-up) effect is observed represented by an increase of domain-wall shift during cyclic switching at constant voltage amplitude. The experimental data are compared to computer simulations taking into account the kinetic imprint effect under ac cycling. The latter is the change of the spatial distribution of the internal bias field during cycling. It is shown that deaging (wake-up) arises for aged (screened) initial states. After long enough cycling, the spatial distribution of the internal bias field becomes steady state and the wall motion becomes reproducible in all its details. The final distribution of the internal bias field does not depend on the initial state of the sample. The activation energies for deaging and aging are equal within the experimental uncertainty and thus very likely stem from the same micromechanism. [ABSTRACT FROM AUTHOR]

Recently, the progress of integrated electronics has led to a strong demand for materials and devices with multiple functions. In this study, we achieved Pb0.985Sm0.01 (Zr0.64Sn0.28Ti0.08)O3 ( PSZST) multifunctional ceramics which showed simultaneously large electric-field-induced strain (0.63%) and high recoverable energy density (1.743 J/cm3) at room temperature. Moreover, the strain and recoverable energy density exhibited a slight frequency fluctuation in the frequency range of 1-10 Hz. Their variations were less than 8% and 1.3% and the values were all higher than 0.58% and 1.722 J/cm3, respectively. The large strain, high-energy density, and their good frequency stability in a wide range indicate that the PSZST ceramic is quite promising for application in multifunctional devices. [ABSTRACT FROM AUTHOR]

The dielectric and electromechanical properties of 0.75 Bi1/2 Na1/2 TiO3-0.25 SrTiO3 (25 ST) as a function of temperature and frequency were studied. It is shown that the 25 ST is a relaxor ferroelectric as evidenced by the temperature-dependent dielectric relaxations with an incipient piezoelectricity featured by the presence of a reversible electric-field-induced phase transformation at room temperature. The transition occurs on a broad electric field strength range depending on field amplitude and frequency. It is also accompanied by a huge strain that is attributed to repetitive poling and depoling originating due to the reversibility of the phase transition. The 25 ST makes an attractive lead-free candidate for stack actuators as it presents a high normalized d33* of ~600 pm/V at a low electric field of 4 kV/mm for frequencies ranging from 0.1 up to 100 Hz. [ABSTRACT FROM AUTHOR]

The single-phase solid solutions of the (1 − x) BaTiO3-( x) Bi( Zn1/2 Ti1/2) O3 ( BT- BZT) where x = 0.02-0.15 were prepared to investigate dielectric properties. Crystal structure of samples was obtained by using an X-ray diffraction technique and Raman spectroscopy. For compositions with x ≤ 0.08, the solid solutions exhibited clear tetragonal symmetry and transitioned to pseudocubic symmetry as the content of BZT increased. The dielectric response exhibited a sharp phase transition within the BT-rich region and the composition 0.92 BT-0.08 BZT was characterized by the onset of relaxor characteristics. As the concentration of BZT increased, the phase transition exhibited broader and more diffuse behavior. The polarization as a function of electric field ( P- E) of these solid solutions also exhibited the same trend. The BT-rich compositions showed a normal ferroelectric P- E response with a decrease in loop area as the BZT content increased. The composition at x = 0.08 exhibited a pinched hysteresis loop and with further increase in BZT content, the P- E response was characterized by slim loops. [ABSTRACT FROM AUTHOR]

This article presents surface electric potential distributions, measured by Kelvin Probe Force Microscopy, on the (001) surface in an indentation-pre-cracked BaTiO3 single crystal with and without applied electric field. The results show that cracks are higher potential regions in comparison to other regions. The higher surface potential is induced by the crack itself in air at room temperature and an applied in-plane electric field cannot change the major feature of the potential distribution across the crack. [ABSTRACT FROM AUTHOR]

The development of the ferroelectric polarization of lead–zirconate–titanate (PZT) bulk ceramics under varying electric fields is examined. Repeated partial switching and backswitching results in a decrease of the switchable polarization, but has no effect on the effective strain. This is attributed to a stabilization of the domain structure, which leads to a decrease of the electric losses. The results are discussed with respect to the effective strain of PZT ceramics for piezoelectric actuators. [ABSTRACT FROM AUTHOR]