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摘要: 采用超声脉冲重合技术,观察LADTGS在压力升至0.8 GPa,温度在20~90 ℃范围内,超声波在晶体中传播的速度及声衰减系数随温度变化的规律,发现在常压下,在64 ℃处声速随温度变化曲线的斜率有明显变化,对应的声衰减也有一明显吸收峰。随压力升高,Tc以约12 ℃/GPa的速率向高温方向移动。这一现象与介电常数的研究结果大致相同。Abstract: The variation of the velocity and attenuation coefficient of ultrasonic wave with temperature in LADTGS crystal in the range from 20 ℃ to 90 ℃ under hydrostatic pressure up to 0.8 GPa has been investigated by means of ultrasonic pulse echo overlap techniques. The slope of the curve of the velocity vs temperature breaks at transition temperature. When the pressure is raised, shifting of Tc toward the higher side with a rate of 12 ℃/GPa was observed.
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Key words:
- crystal /
- ultrasonic /
- phase transition /
- high pressure
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Samara G A. Advance in Pressure, 155. Baranov A I, et al. High-Temperature High-Pressure, 1976, 8: 604. Yao Yushu, et al. Ferroelectric, to be published. 王积方, 等. 物理, 1985, 14(6): 375.
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