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arXiv 0808.3687cond-mat.str-el
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CeRhIn_5量子临界点的电阻率研究

The quantum critical point in CeRhIn_5: a resistivity study

Georg Knebel, Dai Aoki, Jean-Pascal Brison, Jacques Flouquet

摘要:

用电阻率测量方法研究了CeRhIn_5在强磁场下的压力-温度相图。在临界压力p_c = 2.5GPa处发现了明显的量子临界点。超导状态下的场致磁态在最高场之前是稳定的。在p_c处,强磁场下的反铁磁基态非常迅速地坍缩。p_c的明显特征是正常状态下电阻率和非弹性散射项的强烈增强。当压力高于T_c时,没有明显的T2温度依赖关系。通过对强耦合模型中上临界场的分析,给出了耦合参数λ和旋磁比g与压力的关系。没有空间调制的序参量的签名可以证明。并与CeCoIn_5的磁场-温度相图作了详细的比较。通过对CeRhIn_5和CeCoIn_5的比较,指出了在计算超导上临界场H_c2时考虑有效质量与场的关系的重要性。当临界磁场H_(0)小于H_c2(0)$时,超导赝能隙的持续存在可能使反铁磁性粘在H_c2(0)上。

英文摘要:

The pressure--temperature phase diagram of CeRhIn_5 has been studied under high magnetic field by resistivity measurements. Clear signatures of a quantum critical point has been found at a critical pressure of p_c = 2.5 GPa. The field induced magnetic state in the superconducting state is stable up to the highest field. At p_c the antiferromagnetic ground-state under high magnetic field collapses very rapidly. Clear signatures of p_c are the strong enhancement of the resistivity in the normal state and of the inelastic scattering term. No clear T2 temperature dependence could be found for pressures above T_c. From the analysis of the upper critical field within a strong coupling model we present the pressure dependence of the coupling parameter lambda and the gyromagnetic ratio g. No signatures of a spatially modulated order parameter could be evidenced. A detailed comparison with the magnetic field--temperature phase diagram of CeCoIn_5 is given. The comparison between CeRhIn_5 and CeCoIn_5 points out the importance to take into account the field dependence of the effective mass in the calculation of the superconducting upper critical field H_c2. It suggests also that when the magnetic critical field H_(0) becomes lower than H_c2 (0)$, the persistence of a superconducting pseudo-gap may stick the antiferromagnetism to H_c2 (0).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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