Abstract We have studied the enhancement of Kondo scattering in the heavy fermion compounds Ce 2 Ni 3 Ge 1 - x Si x 5 by measuring electrical resistivity ρ ( T ) , magnetic susceptibility χ ( T ) , isothermal magnetization M ( B ) , specific heat C P ( T ) and magnetoresistance. All the members of this series crystallize in U 2 Co 3 Si 5 -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 Ce 2 Ni 3 Ge 1 - x Si x 5 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Ce 2 Ni 3 Ge 5 物理性质的影响

摘要 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，研究了近藤散射在重费米子化合物Ce 2 Ni 3 Ge 1 - x Si x 5 中的增强作用。 CP ( T ) 和磁阻。该系列的所有成员均以U 2 Co 3 Si 5 型斜方晶结构结晶，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 处的单个跃迁，然后完全抑制 x = 0.20 处的反铁磁有序。低于转变温度的正磁阻证实转变是反铁磁性的，直到 x = 0。15 和顺磁性区域的负磁阻意味着在磁场的应用下近藤化合物中的自旋翻转散射冻结。根据顺磁居里温度和磁阻数据估计的近藤温度随着 Ce 2 Ni 3 Ge 1 - x Si x 5 中 x 的增加而增加，x ⩽ 0.80。γ 值还表明近藤温度随着反铁磁有序抑制后 x 的增加而增加。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-非磁性边界处更为明显。对于 T = 3.5 K、3.8 K 和 4 K（x = 0 样品），在特定磁场下观察到电阻率显着增加，并且在 T = 3 K（x = 0.15 样品）时观察到电阻率显着增加。