Pseudogap and transport properties in Fe 3 − x V x Al y ( x = 0.5 – 1 . 0 5 ; y = 0.95 , 1.05 )
Pseudogap and transport properties in Fe 3 − x V x Al y ( x = 0.5 – 1 . 0 5 ; y = 0.95 , 1.05 )
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DOI：
10.1103/physrevb.65.075204
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发表时间：
2002-01
影响因子：
3.7
通讯作者：
A. Matsushita;T. Naka;Y. Takano;T. Takeuchi;T. Shishido;Y. Yamada
中科院分区：
文献类型：
--
作者：
A. Matsushita;T. Naka;Y. Takano;T. Takeuchi;T. Shishido;Y. Yamada
我们测量了金属间化合物${\mathrm{Fe}}_{3\ensuremath{-}x}{\mathrm{V}}_{x}{\mathrm{Al}}_{y}$$(x=0.5char21.05；$$y=0.95，1.05)$的室温霍尔电阻率。随着x值的增加或y值的减小，霍尔系数的符号在Heusler组分(即$x=y=1)附近由正变为负。在5char21300K的温度范围内，我们测量了${\mathrm{Fe}}_{1.98}{\mathrm{V}}_{1.02}\mathrm{Al}$和淬火${\mathrm{Fe}}_{1.95}{\mathrm{V}}_{1.05}\mathrm{Al}$的霍尔系数和电阻率随温度的变化关系，这两种化合物的电阻率表现出非常不同的行为，但霍尔系数的行为是非常相似的。在较高温度下，霍尔系数表现出强烈的温度依赖性，但在较低温度下，霍尔系数接近一个恒定值，这表明这些化合物是具有赝隙的半金属。发现每单位电池的电荷载流子密度不到十分之几。低温下电阻率的上升不是由于能隙，而是由于磁散射，而高温时的负温度系数是由于赝隙。
We have measured the Hall resistivity for the intermetallic compound ${\mathrm{Fe}}_{3\ensuremath{-}x}{\mathrm{V}}_{x}{\mathrm{Al}}_{y}$ $(x=0.5\char21{}1.05;$ $y=0.95,1.05)$ at room temperature. The Hall coefficient changed its sign from positive to negative around the Heusler composition (i.e., $x=y=1)$ with increasing x value or decreasing y value. We have measured the temperature dependence of the Hall coefficient and the electrical resistivity for ${\mathrm{Fe}}_{1.98}{\mathrm{V}}_{1.02}\mathrm{Al}$ and quenched ${\mathrm{Fe}}_{1.95}{\mathrm{V}}_{1.05}\mathrm{Al}$ in the temperature range of 5\char21{}300 K. These two compounds showed very different behavior in the electrical resistivity but the behavior of the Hall coefficient was quite similar. At higher temperatures, the Hall coefficient showed a strong temperature dependence but it approached a constant value at low temperatures suggesting that these compounds are semimetals with a pseudogap. The charge carrier density was found to be less than a few tenths per unit cell. The rise of electrical resistivity at low temperatures is not owing to an energy gap but due to magnetic scattering while the negative temperature coefficient at high temperatures is attributable to pseudogap.