We studied in detail the electrical and magnetic properties of the Eu-divalent antiferromagnet EuTe₂ with a tetragonal crystal structure using single crystals grown by the Te self-flux method. The observed anisotropic magnetization curves in the antiferromagnetic state below T_N = 11.1 K can be understood in terms of the magnetization processes of the two-sublattice model of an antiferromagnet with uniaxial magnetic anisotropy. A characteristic feature of this compound is that it becomes an insulator with decreasing temperature at zero magnetic field, but changes to a metal with a relatively low number of carriers in magnetic fields. From the results of magnetization, magnetoresistance, and Hall resistivity measurements in magnetic fields up to μ₀H = 40 T, the insulator–metal transition was found to occur when the magnetization reaches ∼2 μ_B/Eu for both \(H\parallel [110]\) and [001] at measurement temperatures above 50 K. Energy band calculations revealed that only the up-spin band, which is mainly composed of Te-5p electrons, crosses the Fermi level in the ferromagnetic state, although the energy band possesses a band gap in the paramagnetic and antiferromagnetic states.

中文翻译：

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EuTe2 中场致绝缘体-金属转变

我们使用Te自熔剂法生长的单晶详细研究了具有四方晶体结构的Eu二价反铁磁体EuTe _{2的电学和磁学性质。在}T _N = 11.1 K以下的反铁磁状态下观察到的各向异性磁化曲线可以用具有单轴磁各向异性的反铁磁体的二亚晶格模型的磁化过程来理解。这种化合物的一个特征是，在零磁场下，随着温度的降低，它会变成绝缘体，但在磁场中会变成载流子数量相对较少的金属。根据在高达μ ₀ H = 40 T的磁场中的磁化强度、磁阻和霍尔电阻率测量结果，发现当磁化强度达到 ∼2 μ _B /Eu时，会发生绝缘体-金属转变。\(H\并行[110]\)[001] 在测量温度高于 50 K 时。能带计算表明，只有主要由 Te-5 p电子组成的上自旋能带在铁磁态下穿过费米能级，尽管该能带具有能带顺磁态和反铁磁态的间隙。