STUDY ON SCATTERING OF CONDUCTION ELECTRONS FOR SPIN-FLUCTUATION MEDIATED SUPERCONDUCTOR VIA dHvA EFFECT

利用de Haas-van Alphen（dHvA）效应研究了自旋涨落介导超导体的散射寿命和传导电子的有效质量。我们选取了具有非常规超导性的典型化合物ZrZn_2和CeIn_3分别作为巡游铁磁体和磁有序重费米子系统的材料，通过对ZrZn_2的dHvA效应的压力研究，发现了类似于UGe_2的“嵌套“铁磁压-磁场相图。而ZrZn_2的散射寿命和有效质量没有明显的变化。这一特征与UGe_2的有效质量剧烈变化的特征不同。这些结果表明，传导电子对通过f电子的自旋涨落比d电子的自旋涨落更敏感。CeIn_3的dHvA频率和有效质量在不同的四种压力下有不同的变化。这些连续的传导电子性质的演变与在姊妹化合物CeRh_2Si_2中观察到的传导电子性质的突然变化是完全不同的。虽然大多数由自旋涨落介导的非常规超导体似乎具有相似的相图，但传导电子的精确性质是每个化合物的特征。

Scattering lifetime and effective mass of the conduction electrons for the spin-fluctuation mediated superconductor have been investigated by the de Haas-van Alphen (dHvA) effect. We selected typical compounds ZrZn_2 and CeIn_3 for the itinerant ferromagnet and magnetically ordering heavy Fermion system, respectively, both showing the unconventional superconductivity.Pressure study of dHvA effect on ZrZn_2 revealed"nested"ferromagnetic pressure-magnetic field phase diagram being similar to that of UGe_2. However, no significant changing of the scattering lifetime and the effective mass across the phase boundary was observed in ZrZn_2. Such a feature is different from that of UGe_2 in which drastic changing of the effective mass is observed. These results suggest that the conduction electron is more sensitive for the spin fluctuation through the felectron than the d-electron.vThe dHvA frequency and the effective mass of CeIn_3 change in behavior at distinct four pressures. These successive evolutions of the conduction electron properties are quite different from the sudden changes of them observed in sister compound CeRh_2Si_2. Although most of unconventional superconductors mediated by spin-fluctuation seem to possess a similar phase diagram, precise properties of conduction electrons are characteristic for each compound.