Acoustic properties of oxide glasses at low temperatures.
Acoustic properties of oxide glasses at low temperatures.
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氧化物玻璃在低温下的声学特性。
DOI：
10.1103/physrevb.52.7179
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Würger
中科院分区：
文献类型：
--
作者：
Rau;Enss;Hunklinger;Neu;Würger
用振簧技术研究了a-B 2 O3和a-GeO 2在10 mK< T< 200 K温度范围内的低频声学性质，结果证实了以前对其它非晶陶瓷的测量结果.虽然低温数据在隧道模型的框架下很好地描述了Jäckle的微扰理论，但5 K以上的强弛豫需要不同的方法。高达20 K的非相干隧穿的两级系统似乎管理的弛豫动力学，在更高的温度下的两级描述打破，热激活势垒交叉导致的Arrhenius样的弛豫速率。
Acoustic properties of a-B 2 O 3 and a-GeO 2 are investigated at low frequencies in the temperature range 10 mK< T< 200 K, using a vibrating-reed technique; the results confirm earlier measurements on other amorphous dielectrics. Whereas the low-temperature data are well described by Jäckle’s perturbation theory in the framework of the tunneling model, the strong relaxation above 5 K requires a different approach. Up to 20 K incoherent tunneling of two-level systems seems to govern the relaxational dynamics; at still higher temperature the two-level description breaks down, and thermally activated barrier crossing leads to a Arrhenius-like relaxation rate.