Application Cases

Experimental Name: Electromechanical Performance Testing of Poled Crystals

Test Equipment: High-voltage amplifier, multifunction synthesizer, oscilloscope, LCR meter, computer, etc.

Figure 1: Field-Cooling Poling Setup: (a) Aluminum (Al) Container; (b) Metal Cooling Plate

Experimental Process:

Figure 1 shows the complete system for Direct Current Poling (DCP) and Alternating Current Poling (ACP), including the sample holder for poling, the aluminum (Al) container, and the metal cooling plate used for field-cooling poling. Before the field-cooling poling experiment, the large cooling metal plate with high thermal conductivity and the aluminum (Al) container installed in its circular recess need to be pre-cooled in a freezer to -20°C to achieve rapid cooling from 200°C to 35°C within no more than 12 minutes during the poling process. The experimental setup of the entire poling system is shown in Figure 1(c), which includes the high-voltage amplifier, multifunction synthesizer, and oscilloscope, among other instruments.

Figure 2: (a) FC-DCP and (b) FC-ACP (C: Cubic, T: Tetragonal, M: Monoclinic, R: Rhombohedral)

Schematic diagrams illustrating the voltage versus temperature profiles for Field-Cooling Direct Current Poling (FC-DCP) and Field-Cooling Alternating Current Poling (FC-ACP) are shown in Figures 2(a) and 2(b), respectively. Different poling cooling regions are adjusted based on the phase transition temperature (Tpc) and Curie temperature (Tc) of different crystals, and poling is performed under various field-cooling conditions. To compare the poling voltages between ACP and DCP, the unit of volts RMS per centimeter (Vrms/cm) is used for the ACP voltage. "RMS" (Root Mean Square), also known as the effective value or heating value of AC current, is equivalent to the DC voltage that would produce the same amount of heat in a resistor. Therefore, we used kVrms/cm as the voltage unit for ACP in all experiments to accurately compare all performance aspects with DCP. The RMS voltage (Vrms) of a sinusoidal AC waveform is calculated by multiplying the peak AC voltage (Vpk) by 71% (approximately 1/√2).

Experimental Results:

The temperature-dependent dielectric constant curves and dielectric loss were measured from room temperature to 250°C at 1 kHz, in 0.2°C increments, using a computer-controlled LCR meter. Crystal samples poled under different conditions were subjected to phase analysis using an X-ray diffractometer with CuKα radiation on the (400)pc plane of the single crystal. The measurement method was consistent with that reported by Sun et al.

High-Voltage Amplifier Recommendation: ATA-7030 High-Voltage Amplifier

Figure: ATA-7030 High-Voltage Amplifier Specifications and Parameters