The order (first or second) of transition in KDP crystals is still a problem of controversy. How the spontaneous polarization grows near the phase transition will be a very interesting problem in this respect and can be studied either as a static problem or as a dynamic problem.
In the present work the polarization reversal dynamics of KDP single crystal is investigated near the transition temperature using pulse type input voltage. The resultant output waveforms are displayed on the dual beam oscilloscope and photographed at various temperatures across the transition temperature 123˚K. The results were analyzed and it was found that the piezoelectricity of KDP played an important role in explaining the data. It was also found that orientational relaxations of domains and Barkhausen effects must be incorporated with the piezoelectricity of KDP.
KDP 결정체의 phase transition의 order ( first or second )는 아직도 논의의 대상이 되고 있다. phase transition 부근에서 어떻게 spontaneous polarization이 형성되는지는 매우 흥미있는 문제이며 static 한 면과 dynamic한 면의 연구가 필요하다.
본 실험에서는 phase transition temperature 부근에서 pulse type의 input voltage를 사용하여 KDP single crystal의 polarization reversal dynamics를 조사하였다. Dual beam oscilloscope에 나타난 output voltage의 파형을 여러 온도에서 사진에 담았다. 결과의 분석에는 KDP의 piezoelectricity가 매우 중요한 역할을 함을 알 수 있다. 또한 domain의 orientational relaxation과 Barkhausen effect도 piezoelectricity와 함께 KDP의 polarization switching 을 해석하는데 중요하다.
