The influence of Y- and La-substitution for Ce on the competing Kondo effect and magnetic ordering, as well as on spin dynamics in the Kondo semiconductor CeRu₂Al₁₀ have been investigated by means of thermal, electronic, and magnetic properties. The parent compound CeRu₂Al₁₀ is known to be a controversial antiferromagnet with high magnetic ordering temperature T ₀ = 27K. A small negative chemical pressure caused by La-doping results rapid suppression of T ₀ and spin gap energy Δ _m , compared to a small positive pressure caused by Y-doping. Upon Y- and La-doping, the electrical resistivity ρ(T) illustrates the evolution from dense Kondo semiconductor to incoherent single-ion Kondo behaviour, and hence weakens the c–f hybridization and thus lowers the Kondo temperature. The 5% Y- and La-doped compounds show enormous enhancement in the thermoelectric power and complex behaviour in the Hall resistivity below T ₀ due to an abrupt change in charge carrier mobility with temperature. The magnetic contribution to electrical resistivity ρ _mag(T) (≳50% La) and specific heat C _P(T)/T (≳70% La) evidence non-Fermi-liquid behaviour at low temperature in the La-doped system, due to interplay of atomic disorder with spin-fluctuation. Application of magnetic field suppresses the spin-fluctuation in C _P(T)/T and eventually emerges to Fermi-liquid state in the 95% La-doped compound in 9T. The magnetic phase diagram illustrates that the strength of the Kondo interaction in the doped systems are primarily controlled by the effect of volume change as described by the compressible Kondo lattice model. We ascribe the fascinating observation of T _K ≃ 4T ₀ to anisotropy in the single-ion crystal electric field in the presence of strong anisotropic c–f hybridization.

已经通过热、电子和磁特性研究了Y 和 La 取代 Ce 对竞争的 Kondo 效应和磁排序的影响，以及对 Kondo 半导体 CeRu ₂ Al _{10 中}自旋动力学的影响。已知母体化合物 CeRu ₂ Al ₁₀是一种有争议的反铁磁体，具有高磁有序温度T ₀ = 27K。与由 Y 掺杂引起的小的正压力相比，由 La 掺杂引起的小的负化学压力导致T ₀和自旋间隙能量 Δ _{m 的}快速抑制。在 Y 和 La 掺杂后，电阻率ρ ( T ) 说明了从密集近藤半导体到非相干单离子近藤行为的演变，从而削弱了c - f杂化，从而降低了近藤温度。由于电荷载流子迁移率随温度的突然变化，5% Y 和 La 掺杂的化合物在热电功率和低于T ₀的霍尔电阻率的复杂行为方面表现出巨大的增强。对电阻率ρ _mag ( T ) (≳50% La) 和比热C _P ( T )/ T的磁性贡献(≳70% La) 证明了 La 掺杂系统在低温下的非费米液体行为，这是由于原子无序与自旋波动的相互作用。磁场的应用抑制了C _P ( T )/ T 中的自旋波动，并最终在 9T 中的 95% La 掺杂化合物中出现费米液态。磁相图说明掺杂系统中近藤相互作用的强度主要受可压缩近藤晶格模型描述的体积变化效应的控制。我们将T _K ≃ 4 T ₀的迷人观察归因于在强各向异性c存在下单离子晶体电场中的各向异性– f杂交。