NiS2-xSex在x=1.00附近的反铁磁量子相变

针对NiS_2-xSe_x系统在x=1.0０附近发生的反铁磁量子相变，制备了一系列NiS_2-xSe_x(x=0.96, 0.98, 1.00, 1.05, 1.10和1.20)多晶样品，对其结构、磁性质和电阻率进行了系统的观测.结果发现：样品磁化率-温度关系呈现典型的强关联电子系统特征；与铜氧化物超导体相类似，它们的电阻率-温度关系在很宽的温 关键词： 量子相变 反铁磁自旋涨落 2-xSe_x体系')" href="#">NiS_2-xSe_x体系

Antiferromagnetic quantum phase transition near x=1.00 in NiS2-xSex system

There may be an antiferromagnetic quantum phase transition near x=1.0０ in NiS_2-xSe_x system. The polycrystalline samples of NiS_2-xSe_x (x=0.96, 0.98, 1.00, 1.05, 1.10 and 1.20) were prepared by the solid state reaction method, and the measurements of their structure, magnetization and resistivity were carried out. It is found that the temperature dependence of susceptibility is typical characteristic of a strongly correlated electron system. Similar to high T_c superconductors, the relationship between resistivity and temperature displays a linear behavior in a wide temperature range from 50 to 300 K. For NiS_2-xSe_x(x=0.98 and 1.00) samples, its ρ(T) is proportional to T^3/2 at lower temperatures (3—30 K), which shows a non-Fermi-liquid behavior. But for NiS_2-xSe_x (x=1.10 and 1.20) samples, its ρ(T) is proooportional to T² at lower temperatures (3—30 K), which shown the Fermi-liquid behavior. The antiferromagnetic quantum spin fluctuation related to quantum phase transition is discussed in detail.