中文摘要：

针对Co（S1-xSex）2系统在x=0.11附近发生的铁磁金属到顺磁金属相变,制备了一系列不同Se替代浓度的多晶样品.通过对其结构和电阻率-温度ρ（T）关系的系统观测,结果发现,样品铁磁相变温度TC随着Se替代浓度x值的增加,以（1-x）1/2关系单调下降,其二级铁磁相变转变为一级相变;在临界浓度x=0.11附近,其ρ（T）关系由Fermi液体行为转变为非Fermi液体行为.作者认为,Co（S1-xSex）2系统在x=0.11附近发生的是一种量子相变,在该量子相变点附近零温度下的自旋量子涨落导致其ρ（T）关系的反常行为.

英文摘要：

In Co（S1-xSex）2 system, a transition from ferromagnetic to paramagnetic state occurs near x=0.11. In order to research the physical properties of the samples near this transition, polycrystalline samples of Co（S1-x Sex）2 （0.0≤x≤ 0.16） were prepared. And their structure and resistivity were measured. It is found that the ferromagnetic transition temperature TC is suppressed by Se doping in the relation TC～（1-x）^1/2. And the ferromagnetic phase transition goes from the second to the first order. The temperature dependence of resistivity, ρ（T）, shows a Fermi-liquid behavior,ρ（T）=ρ0＋AT^2, in Co（S 1-x Sex）2 （x 〈 0.08） samples, while the non-Fermi liquid behavior of ρ（T） occurs in the samples near a critical concentration x=0.11. It is suggested that the phase transition near x=0.11 is a quantum phase transition, and the quantum critical spin fluctuation at zero temperature results in non-Fermi liquid behavior.