講演題目：High Pressure Studies on Yb Heavy-Fermion Systems near a Quantum Critical Point

講師：Prof. M. Abd-Elmeguid

所属：ケルン大学

日時：2006年8月3日（木）13時から

場所：先端科学総合研究棟４０１Ｎ





アブストラクト：

The discovery that some Yb intermetallic compounds reveal many of the interesting Kondo-related properties found in Ce compounds has generated considerable excitement.



Towards a better understanding of the ground state properties of this class of materials, we have investigated the effect of pressure on the magnetic and electronic properties of the nonmagnetic (NM) heavy fermion (HF) systems located near a magnetic quantum critical point (QCP) (e.g. Yb₂Ni₂Al, YbCu₂Si₂ and YbRh₂Si₂) using the ¹⁷⁰Yb mossbauer effect, electrical resistance and x-ray diffraction techniques. In all compounds we find microscopic evidence for a pressure-induced phase transition (first-order) from the nonmagnetic state to a magnetically ordered state of Yb local moments.



In the case of YbRh₂Si₂, we show that by crossing the QCP spin fluctuations exist up to very high pressures. A new magnetic phase diagram in the (p,T) space is suggested. Future work on new Yb-based HF systems will be discussed.



担当： 高畠　敏郎（先端）内線7025



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