Transport properties in CeOs4Sb12 : Possibility of the ground state being semiconducting
Transport properties in CeOs4Sb12 : Possibility of the ground state being semiconducting
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DOI：
10.1103/physrevb.71.125127
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发表时间：
2004-12
影响因子：
3.7
通讯作者：
H. Sugawara;S. Osaki;M. Kobayashi;T. Namiki;S. Saha;Y. Aoki;H. Sato
中科院分区：
文献类型：
--
作者：
H. Sugawara;S. Osaki;M. Kobayashi;T. Namiki;S. Saha;Y. Aoki;H. Sato
我们测量了ceo $_4$ Sb $_{12}$的磁阻和霍尔效应，以澄清大电阻率状态归因于近道绝缘状态和比热测量中报告的0.9 K附近相变的起源。我们发现在低于$\sim30$ K约两个数量级的宽温度范围内，电阻率$\rho\sim T^{-1/2}$和霍尔系数$R_{\rm H}\sim T^{\rm -1}$对温度（$T$）的依赖性不同寻常，这可以解释为载流子密度和载流子散射对温度的依赖性的综合效应。在输运性质中已经清楚地观察到与相变有关的异常，由此确定了$H-T$相图，直至14 t。考虑到小的熵变，相变很可能是自旋密度波。在0.3 K处的电阻率和霍尔电阻率都被$\sim3$ T以上的磁场大大抑制了一个数量级，这表明在磁场作用下电子结构发生了剧烈变化，自旋涨落受到抑制。
We have measured both magnetoresistance and Hall effect in CeOs$_4$Sb$_{12}$ to clarify the large resistivity state ascribed to the Kondo insulating one and the origin of the phase transition near 0.9 K reported in the specific heat measurement. We found unusual temperature ($T$) dependence both in the electrical resistivity $\rho\sim T^{-1/2}$ and the Hall coefficient $R_{\rm H}\sim T^{\rm -1}$ over the wide temperature range of about two order of magnitude below $\sim30$ K, which can be explained as a combined effect of the temperature dependences of carrier density and carrier scattering by spin fluctuation. An anomaly related with the phase transition has been clearly observed in the transport properties, from which the $H-T$ phase diagram is determined up to 14 T. Taking into account the small entropy change, the phase transition is most probably the spin density wave one. Both the electrical resistivity and Hall resistivity at 0.3 K is largely suppressed about an order of magnitude by magnetic fields above $\sim3$ T, suggesting a drastic change of electronic structure and a suppression of spin fluctuations under magnetic fields.