Elastic and Acoustic Measurements in Solid 4He
Elastic and Acoustic Measurements in Solid 4He
复制标题
固体 4He 中的弹性和声学测量
DOI：
--
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
A. Penzev
中科院分区：
文献类型：
--
作者：
Y. Mukharsky;A. Penzev
我们描述了在观察到超固体的参数范围内固体氦的弹性和声学测量结果。对各种多晶和单晶样品进行了研究。我们观察到多晶样品的单轴压缩模数随温度的降低最高可达25%。这种软化通常用Hcp4He固体的基面剪切模数c44的降低来解释。根据模型的不同，我们的结果转化为组成晶体的c44减少了77%到82%。在声学测量中，我们试图通过将观测到的共振频率与数值计算进行拟合来检查通过c44进行软化的描述是否合适。无论是测量到的位置，还是共振的线形，都不符合低温下的模拟，这表明需要另一种方法。
We describe results of elastic and acoustic measurements in solid helium in the range of parameters where supersolidity is observed. A variety of polycrystalline and mono-crystalline samples has been studied. We observed a decrease with temperature of the uniaxial compression modulus in a polycrystalline sample by up to 25 %. Such softening is usually explained in term of decrease of base-plane shear modulus, c44, of hcp4He solid. Our results translates into a decrease of c44 of the constituent crystallites between 77 % and 82 %, depending on the model. In the acoustic measurements, we attempted to check whether the description of softening via c44 is appropriate by fitting frequencies of observed resonances to numerical calculations. Neither the measured positions, nor the line shapes of the resonances fit the simulations at low temperatures, indicating that an alternative approach is required.