Switching 70Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 single crystal by 3 MHz bipolar field

Abstract

Polarization switching and associated electromechanical property changes at 3.0 MHz were investigated with and without a direct current (dc) bias for [001] poled 0.70Pb(MgNb)O-0.30PbTiO single crystal. The results showed that the coercive field under a bipolar pulse at 3.0 MHz is 2.75 times as large as conventional defined (2.58 kV/cm at 0.1 Hz), and a dc bias can further enlarge the driving field. Our results point to an innovative transducer operating mechanism at high frequencies since one could drive the crystal under much larger fields at high frequencies to produce much stronger signals from a small array element for deeper penetration imaging.

Depoling and fatigue behavior of Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal at megahertz frequencies under bipolar electric field

“…Therefore, we have defined an effective coercive field of the ferroelectric material at megahertz frequencies in an earlier report. 23 In our experiments, the amplitude of the bipolar electric field at which the electromechanical coupling factor k t begins to decrease with the increasing loading cycles is defined as the effective coercive field at that frequency.…”

“…1(b) that the phase angle of the impedance spectrum shows a similar variation. According to a previous report, 23 the critical electric field at which the anti-resonance frequency peak begins to shift to lower frequency can be considered as the effective coercive field at the testing frequency. Accordingly, the effective coercive field of the PMN-0.29PT single crystal at 4 MHz was measured to be 575 V/mm, which is nearly 3 times as large as the conventionally defined E c (191 V/mm at 0.1 Hz).…”

“…The impedance spectra were measured by an impedance analyzer (HP 4294A) and then, the electromechanical coupling factor k t was determined by the resonance and anti-resonance frequencies of the thickness vibration mode. 23 Relative dielectric constant e r and dielectric loss D were measured by an LCR meter (SRS SR715) at 1 kHz. Piezoelectric coefficient d 33 was measured by a d 33 meter (Piezotest PM300).…”

Frequency dependence of the coercive field of 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 single crystal from 0.01 Hz to 5 MHz

“…[1][2][3] In general, E c is frequency dependent because polarization switching is associated with domain wall motions and/or opposite domain nucleation and growth, both processes are time and field dependent. 1,2,4 The frequency dependence of the coercive field of bulk ferroelectric single crystals or ceramics had been investigated by measuring the polarization hysteresis loops in the low frequency range of 0.01 Hz-1000 Hz.…”

“…The high frequency coercive field from 10 kHz to 5 MHz was measured using a critical value method based on ferroelectric degradation. 3 In this method, a pulse/ function generator (Wavetek Model 81) was used to generate a sinusoidal pulse signal, and then, the signal was amplified using a RF broadband power amplifier (Electronics & Innovation 1040L, 10 kHz-5 MHz). The amplified signal was output to the samples and oscilloscope through a "T" connection.…”