Time-resolved x-ray diffraction study of the piezoelectric crystal response to a fast change of an applied electric field

Abstract

Time-resolved measurements of the macroscopic and microscopic strains in piezoelectric crystals were performed with a novel data acquisition technique implemented on the basis of a field programmed gate array system. Both types of strains were induced in a crystal by an applied periodic high voltage with fast (within 100 ns) switches between opposite polarities and measured simultaneously by respective angular shifts and integrated intensities of synchrotron x-ray diffraction rocking curves. The time resolution achieved with the developed data acquisition system was 100 ns. The paper demonstrates the particular application of this technique for the investigations of time dynamics of lattice constants and atomic positions in a unit cell for piezoelectric BiB3O6 and Li2SO4 center dot H2O crystals. It has been found that 100 ns fast rising time of an applied external electric field induces oscillations of the crystal lattice constants, visible as oscillations of Bragg peak angular positions. At the same time, these oscillations are not observed for the Bragg intensities, i.e., for fractional positions of atoms in the unit cell and correspondingly for bond lengths. The results allow suggesting a model for the mutual interconnection between the deformation of bond lengths and lattice constants in piezoelectric crystals. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3480996]\u

Structural contribution to the ferroelectric fatigue in lead zirconate titanate ceramics

“…4 shows the characteristic 200 c reflection for the unfatigued and fatigued sample respectively as a function of the applied electric field for rectangular on-off stroboscopic pump-probe measurements. It clearly demonstrates that the field induced structural response has a time scale in the range of hundreds of microseconds as observed based on macroscopic strain measurements [22][23][24] . After 1.5 ms, no further structural changes were observed.…”

Crystallography under External Electric Field

“…The discontinuity appearing at the 5001st time channel corresponds to the change in the HV polarity -at this point the average position of the peak maximum displaces accordingly and oscillates around a new position. [52] Figure 9. The normalized response of a damped harmonic oscillator, q(t) k/F 0 (oscillating curve), to the dynamical switch of external force, F(t)/F 0 (smooth curve).…”

“…The fast switch of the force generates high-amplitude oscillations of the displacements; the slow switch of the force induces lower-amplitude oscillations; further increase of the rising time removes the oscillations: the response will be proportional to the force as in a static case. [52] www.zaac.wiley-vch.de the elastic deformation propagating back and force in the crystal; the frequencies of the oscillations (eigen-frequencies of the crystal plate) depend on the geometry of the crystal and its elastic constants / sound velocities.…”

Time-resolved photoemission spectroscopy on a metal/ferroelectric heterostructure

“…Ideally, these techniques should be independent of the electrical circuit required to switch the polarization. For instance, Gorfman et al used time-resolved x-ray diffraction to determine the lattice dynamics and atomic positions in piezoelectrics 13 . X-ray photoemission spectroscopy (XPS) is a powerful, direct tool for characterizing the chemical and electronic interface structure.…”