We have studied the enhancement of Kondo scattering in the heavy fermion compounds Ce2Ni3Ge1-xSix5 by measuring electrical resistivity ρ(T), magnetic susceptibility χ(T), isothermal magnetization M(B), specific heat CP(T) and magnetoresistance. All the members of this series crystallize in U2Co3Si5-type orthorhombic structure with space group Ibam. Magnetic susceptibility and specific heat data show that two step antiferromagnetic transitions at x = 0 reduce to a single transition at x = 0.15 followed by a complete suppression of antiferromagnetic ordering at x = 0.20. Positive magnetoresistance below the transition temperature confirms that the transitions are antiferromagnetic up to x = 0.15 and the negative magnetoresistance in the paramagnetic region implies the freezing out of spin-flip scattering in Kondo compounds under the application of magnetic field. Kondo temperature, estimated from paramagnetic Curie temperature and magnetoresistance data, increases with increasing x in Ce2Ni3Ge1-xSix5 for x⩽0.80. The γ values also indicate that the Kondo temperature enhances with increasing x after the suppression of antiferromagnetic ordering. Maximum γ value (∼76 mJ mol−1 K−2 Ce−1) is observed at x = 0.20 which indicates that the heavy fermion behavior is more pronounced at the magnetic-nonmagnetic boundary. A significant resistivity increase at a particular magnetic field is observed for T = 3.5 K, 3.8 K and 4 K (x = 0 sample) and it is observed for T = 3 K (x = 0.15 sample).

中文翻译：

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化学压力对反铁磁近藤晶格Ce2Ni3Ge5物理性质的影响


我们通过测量电阻率ρ(T)、磁化率χ(T)、等温磁化强度M(B)、比热CP(T)和磁阻，研究了重费米子化合物Ce2Ni3Ge1-xSix5中近藤散射的增强。该系列的所有成员均以 U2Co3Si5 型斜方结构结晶，空间群为 Ibam。磁化率和比热数据表明，x = 0 处的两步反铁磁跃迁减少为 x = 0.15 处的单跃迁，随后在 x = 0.20 处完全抑制反铁磁有序化。低于转变温度的正磁阻证实了转变在 x = 0.15 范围内是反铁磁性的，顺磁区域的负磁阻意味着近藤化合物在磁场作用下自旋翻转散射被冻结。根据顺磁居里温度和磁阻数据估计的近藤温度随着 Ce2Ni3Ge1-xSix5 中 x 的增加而增加，其中 x⩽0.80。 γ 值还表明，在抑制反铁磁有序之后，近藤温度随着 x 的增加而增强。在 x = 0.20 处观察到最大 γ 值（∼76 mJ mol−1 K−2 Ce−1），这表明重费米子行为在磁性-非磁性边界处更加明显。对于 T = 3.5 K、3.8 K 和 4 K（x = 0 样本），在特定磁场下观察到电阻率显着增加，对于 T = 3 K（x = 0.15 样本）也观察到电阻率显着增加。