Application Cases

Experimental Name: Performance Analysis of Piezoelectric Array Elements under Different AC Poling Parameters

Test Equipment: High-voltage amplifier, function generator, oscilloscope, high-precision automatic grinding machine, etc.

Figure 1: (a) Schematic diagram of DC poling, (b) Schematic diagram of AC poling, (c) AC poling setup

Experimental Process:
First, [001]-oriented PIMNT crystals and PZT-5H ceramic plates with dimensions of 5mm × 5mm × 0.5mm were ground down to 0.2mm using a high-precision automatic grinding machine. Considering that the surface stress induced by grinding might degrade the sample performance, the plates were annealed at 600°C for 10 hours. Then, the samples were cut into 2.5mm × 2.5mm × 0.2mm pieces using a high-precision DAD322 automatic dicing machine to avoid defects at the plate edges caused by grinding. Finally, gold electrodes were deposited on both surfaces of the samples by magnetron sputtering, with an electrode thickness of approximately 100 μm. The PIMNT single crystals were poled along the [001] direction by either DCP or ACP in air, while the PZT-5H ceramics were poled by DCP. Schematic diagrams of the DC and AC poling conditions are shown in Figures 1(a) and 1(b), respectively. A schematic diagram of the poling experimental setup is shown in Figure 1(c).

Experimental Results:

Figure 2: (a) Piezoelectric coefficient, relative permittivity, and electromechanical coupling factor of PIMNT crystals as a function of ACP frequency (@10 kV/cm and 10 cycles), (b) Impedance of ACP PIMNT single crystal (@10 kV/cm and 15 Hz).

The relationship between the properties of PIMNT crystals and the poling frequency, poling electric field, and number of cycles was experimentally investigated. As shown in Figure 2, the piezoelectric coefficient, relative permittivity, and electromechanical coupling factor of the PIMNT crystals were studied as functions of the AC poling frequency. It can be observed from the figure that the piezoelectric coefficient of the crystal gradually increases with higher poling frequencies, reaching a maximum value at a frequency of 10 Hz.

Figure 3: (a) Piezoelectric coefficient, relative permittivity, and electromechanical coupling factor of PIMNT crystals as a function of ACP electric field (@10 Hz and 10 cycles), (b) Impedance of ACP PIMNT single crystal (@10 kV/cm and 10 cycles).

Figure 3 shows the coefficients of the PIMNT single crystal, where the poling frequency and number of cycles were fixed at 10 Hz and 10 cycles, respectively. The coefficients increase with the rising AC electric field, showing a generally similar trend. Notably, at an electric field of 10 kV/cm, the piezoelectric coefficient d₃₃ of the AC-poled PIMNT single crystal reached 1405 pC/N, compared to 1147 pC/N for the DC-poled sample, representing a 22.5% improvement with ACP. Concurrently, the single crystal maintained high relative permittivity and a large electromechanical coupling factor after AC poling. However, when the electric field reached 20 kV/cm, the wafer was prone to cracking. Therefore, the electric field should be maintained within the range of 10-18 kV/cm to ensure sample integrity while obtaining sample materials with excellent performance.

High-Voltage Amplifier Recommendation: ATA-7050 High-Voltage Amplifier

Figure: ATA-7050 High-Voltage Amplifier Specifications and Parameters

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