Thermal diffusivity measurement in a diamond anvil cell using a light pulse thermoreflectance technique
Thermal diffusivity measurement in a diamond anvil cell using a light pulse thermoreflectance technique
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DOI：
10.1088/0957-0233/22/2/024011
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发表时间：
2011-02
影响因子：
2.4
通讯作者：
T. Yagi;K. Ohta;Kenichi P. Kobayashi;N. Taketoshi;K. Hirose;T. Baba
中科院分区：
文献类型：
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作者：
T. Yagi;K. Ohta;Kenichi P. Kobayashi;N. Taketoshi;K. Hirose;T. Baba
开发了在高压下测量金刚石砧之间的板的热扩散率的装置。使用两面镀有 Pt 薄膜的 Mg(OH)2 板来测试该装置。 Pt薄膜的一侧起到激光脉冲吸收体的作用，另一侧用于检测温度变化。将样品与作为压力介质的 NaCl 绝缘层一起装入铼箔垫圈中钻的孔中。随后，用 150 µm 底尖斜角金刚石砧压缩样品。本研究中的压力达到了57 GPa。然后，用持续时间为2 ns、波长为1064 nm的激光脉冲加热样品的正面。为了探测样品背面的温度变化，照射了波长为 782 nm 的连续波激光束。利用连续波激光束的反射强度，测量热量穿过 Pt/Mg(OH)2/Pt 层传递时的瞬态温度曲线。通过分析瞬态温度曲线计算了Mg(OH)2的热扩散率。 57 GPa 下 Mg(OH)2 的热扩散率为 5.9 × 10−6 m2 s−1，比环境压力下大约 6 倍。
Apparatus to measure the thermal diffusivity of a plate between diamond anvils at high pressure was developed. The Mg(OH)2 plates coated with Pt films on both sides were used for testing the apparatus. One side of the Pt film played the role of an absorber of a laser pulse, and the other side was used for the detection of the temperature change. The sample was loaded into a hole drilled in a rhenium foil gasket together with the insulation layers of NaCl as a pressure medium. Subsequently, the sample was compressed with 150 µm culet beveled diamond anvils. The pressure in this study reached 57 GPa. Then, a front face of the sample was heated by laser pulses with a duration of 2 ns and a wavelength of 1064 nm. To probe the temperature change at the back face of the sample, a continuous wave laser beam with a wavelength of 782 nm was irradiated. Using the reflected intensity of the continuous wave laser beam, a transient temperature curve was measured when the heat transferred across Pt/Mg(OH)2/Pt layers. The thermal diffusivity of Mg(OH)2 was calculated by analyzing the transient temperature curves. The thermal diffusivity of Mg(OH)2 is 5.9 × 10−6 m2 s−1 at 57 GPa, which is larger than that at ambient pressure by a factor of ≈6.