The low-temperature variation of the elastic constants of lithium hydride and lithium deuteride
The low-temperature variation of the elastic constants of lithium hydride and lithium deuteride
复制标题
氢化锂和氘化锂弹性常数的低温变化
DOI：
10.1088/0022-3719/15/31/009
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
H. Kheyrandish
中科院分区：
文献类型：
--
作者：
B. W. James;H. Kheyrandish
在4.2- 300 K温度范围内测量了7 LiH和7 LiD的超声波通过单晶的渡越时间，得到了它们的绝热弹性常数C_（11）、C_（12）和C_（44）。温度变化非常接近近似Cij（T）=Cij（0）（1-D θ）。用各向异性因子A= C_（44）/（C_（11）-C_（12））和偏离柯西关系式（Δ = C_（12）-C_（44））与碱金属卤化物作了比较。结果表明，在50 ~ 270 K温度范围内，7 LiH和7 LiD的Gruneisen参数γ近似为1.2。有迹象表明，在11 K区域的弹性常数的异常行为，在那里一个λ型热容异常已被报道。
The adiabatic elastic constants C11, C12 and C44 of 7LiH and 7LiD have been obtained from measurements of ultrasonic wave transit times through single crystals over the range 4.2-300K. The temperature variation follows quite closely the approximation Cij(T)=Cij(0)(1-D epsilon ). The anisotropy factor A=C44/(C11-C12) and the deviation ( Delta =C12-C44) from the Cauchy relation have been used to make comparisons with the alkali halides. It has been found that the Gruneisen parameter gamma is approximately constant at 1.2 for both 7LiH and 7LiD from 50 to 270K. There are signs of anomalous behaviour of the elastic constants in the region of 11K, where a lambda -type heat capacity anomaly has been reported.