Electrical and thermal transport properties of intermediate-valence YbAl3
Electrical and thermal transport properties of intermediate-valence YbAl3
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DOI：
10.1088/0022-3727/35/17/315
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发表时间：
2002-08
期刊：
影响因子：
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通讯作者：
D. Rowe;V. Kuznetsov;L. Kuznetsova;G. Min
中科院分区：
文献类型：
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作者：
D. Rowe;V. Kuznetsov;L. Kuznetsova;G. Min
采用Bridgman法合成了中间价化合物YbAl_3。测量了YbAl_3热压样品和单晶样品的塞贝克系数、电阻率和热导率随温度的变化关系。在低于100 K的温度下，电阻率表现出ρ（T）= ρ0 + Δ T2的依赖性，而在300-800 K的温度范围内，YbAl 3表现出金属行为，电阻率与温度呈线性关系。塞贝克系数表现出典型的重费米子化合物的温度依赖性，在200-250 K附近达到最大绝对值-79 µV K-1。大的Seebeck系数和低的剩余电阻率相结合的单晶YbAl 3导致有史以来最高的电功率因数为340×10-6 W cm-1 K-2在80 K。热导率作为温度的函数在50 K处有一个宽峰，这主要源于电子对热导率的贡献。在300 K时，热压样品的总热导率范围为0.085至0.179 W cm-1 K-1，这取决于样品的密度。计算的优值在100-120 K时达到最大值1×10-3 K-1。
Intermediate valence compound YbAl3 has been synthesized by the Bridgman method. Temperature dependence of the Seebeck coefficient, electrical resistivity and thermal conductivity has been measured on YbAl3 hot-pressed and single crystal samples. At temperatures below 100 K, the electrical resistivity exhibits a ρ(T) = ρ0 + AT2 dependence, while over the temperature range 300-800 K YbAl3 exhibits metallic behaviour with a linear temperature dependence of the electrical resistivity. The Seebeck coefficient exhibits a temperature dependence typical for heavy fermion compounds and attains a maximum of its absolute value of -79 µV K-1 at around 200-250 K. Combination of a large Seebeck coefficient and low residual resistivity of single crystalline YbAl3 leads to the highest ever reported electrical power factor of 340×10-6 W cm-1 K-2 at 80 K. Thermal conductivity as a function of temperature has a broad peak at 50 K, which originated mainly from the electronic contribution to thermal conductivity. At 300 K the total thermal conductivity of hot-pressed samples ranges from 0.085 to 0.179 W cm-1 K-1 depending on the density of the samples. The calculated figure of merit value attains its maximum of 1×10-3 K-1 at 100-120 K.