This standard is applicable to the measurement of the pyroelectric coefficient of triglycine sulfate family and tantalate pyroelectric single crystal materials. This method is also applicable to the measurement of the pyroelectric coefficient of other single crystals, ceramics and organic pyroelectric materials with a pyroelectric coefficient above 1×10-9C/(cm2·℃). GB 11297.8-1989 Test method for pyroelectric coefficient of pyroelectric materials GB11297.8-1989 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for pyroelectric coefficient of pyroeleciric materials
UDC 621. 315. 592
. 9 :621. 317. 3
GB 11297. 8--89
This standard is applicable to the measurement of the pyroelectric coefficient of triglycine sulfate family and lithium molybdate pyroelectric single crystal materials. This method is also applicable to the measurement of the pyroelectric coefficient of other single crystals, ceramics and organic pyroelectric materials with a pyroelectric coefficient above the order of 1×10-\C/(cm-r). 1 Terminology
The definitions of terms in this standard are in accordance with GB11294 "Common Terminology of Semiconductor Optoelectronic Materials and Pyroelectric Materials in Infrared Detection Materials".
2 Measurement Principle
This standard uses the charge integration method to measure the pyroelectric coefficient of pyroelectric materials. The figure is a measurement principle diagram. The induced charge released by the pyroelectric crystal heating shield accumulates on the parallel negative feedback capacitor C of the high input impedance amplifier. Since the input end of the charge integration circuit is a virtual ground, the sample is basically in a zero electric field state during the measurement process. The charge integration circuit has a sufficiently large discharge time constant to ensure that the change in output voltage AV. is proportional to the change in polarization intensity of the sample caused by the temperature change △P.: AV.= AP,·A
Where: AV,—change in output voltage, V; AP,——change in polarization intensity, C/cm\; A——sample electrode area, cm2;
Cr-capacitance value of the integration capacitor, F. wwW.bzxz.Net
Measure the V,-T curve, and find the slope of the curve at temperature T to get the pyroelectric coefficient: pr =
Or, measure T\ centered on temperature T and the corresponding △V. value respectively to get the pyroelectric coefficient: P, - [会) =(),
Where: pr---pyroelectric coefficient at temperature, C/(cm\.C); C--capacitance of integrating capacitor, μF; A sample electrode area cm\
d) or (
---differential of output voltage of charge integrating circuit with temperature at temperature T For materials such as ceramics, the actual measured value should be the rate of change of residual polarization intensity P with temperature. Approved by the Ministry of Machinery and Electronics Industry of the People's Republic of China on October 9, 198861)
Implementation on January 1, 1990
3 Test conditions
B. Sample preparation
GB 11297.8: 89
Test Schematic Diagram
Integrating capacitor: 2 High input impedance amplifier: 3--XY recorder DC digital voltmeter and potentiometer: 4--Ice water mixture $5--Thermocouple or other temperature sensitive element; 6--Heating furnace; 7 Sample 3.1.1 The thickness direction of the sample must be consistent with the spontaneous polarization direction, and the deviation angle is less than 2°. The sample surface must be flat and clean. 8.1.2 The two surfaces of the sample must be firmly covered with metal electrodes. 3.1.3 The sample must be fully polarized before measurement. 3.1.4 The thickness of the sample should be less than 0.1 cm. The surface rent should be 0.2~~0.5 cm31.5 The DC resistance of the sample should be greater than 1×10°9.3.2 Sample holder
Test results require the use of a screen. The temperature of the sample should be uniform, and the temperature sensitive element must be close to the sample and electrically insulated. If the measurement starts from below air temperature, the sample holder must be sealed or evacuated to prevent the sample from getting wet. 3.3 The heating rate should be 2~5℃/min.
3.4 ​​For samples of materials such as tris(II) hydrochloric acid sulfate, they should be short-circuited in a dry environment (humidity below 60%) for more than 24 hours before measurement, and the sample holder should be installed in the specified medium environment. When the measurement starts, the two electrodes should be kept open. 3.5 The pyroelectric coefficient given should indicate the test temperature. For ease of comparison, the pyroelectric coefficient at 25℃ is generally given. 4 Test method
4.1 The test circuit is shown in the figure.
4.2 Requirements for test equipment
4.2.1 The temperature sensing element should be selected with greater sensitivity at room temperature. It is recommended to use nickel-chromium-nickel-silicon thermocouples or platinum resistance thermometers. The "bar" should be calibrated by the measurement unit or with a primary standard thermometer. 4.2.2 The input impedance of the amplifier should be greater than 1×101Ω, the open-loop gain should be greater than 5×10t, and the zero drift should be less than (.6) within 10 min. mV4.2.3 The nominal value of the integral capacitor is 1μF. Before use, use a precision capacitor bridge with an accuracy better than ±0.02% to measure its accurate value. Its leakage current should be greater than T-1×10\0 to ensure that the integral time constant is above 10. Polyethylene capacitors are recommended. GB11297.8-89
4.2.4 The sensitivity of the DC digital voltmeter should be 1μV/word, and its accuracy should be better than 0.02% (measured voltage reading) + 2 words; UJ31 type is recommended for potentiometers. ||t t||4.2.5 The relative error of the X-Y recorder should not be greater than 0.8%, and the temperature axis should be selected with a range of 0.2mV/cm or higher. 4.3 Measurement steps
The sample needs to be placed in a sample rack in a dry environment, and the sample rack is placed in a heating furnace. Without connecting the sample, carefully adjust the zero drift of the charge integration circuit to meet the requirements of Article 4.2.2, then connect the sample to the amplifier, adjust the test instrument to the required range, heat the sample and start recording.
If using XY The recorder makes a V.T curve, then the slope at temperature T is obtained. If a digital voltmeter or other instrument is used to measure AT and the corresponding △V centered at temperature T, AT should be not greater than 1 to ensure that the change of the pyroelectric coefficient within the T range is less than the test error. 4.4 Calculation of pyroelectric coefficient
According to formula (2) or formula (3), the pyroelectric coefficient at temperature T can be calculated. 5 Test accuracy
The test error of the standard method is less than ±5%. Additional remarks:
This standard was drafted by the Shanghai Institute of Technical Physics, Chinese Academy of Sciences and the 11th Institute of Mechanical and Electronics Industry. The main drafters of this standard are Da Wei Zhongquan and Yin Jie.
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