Lattice, Ce-L3 edge, resistivity, and magnetic susceptibility measurements have been carried out on the polycrystalline Ce1-xLaxMn2Si2 system (0≤x≤1) to study the interplay between Mn 3d-host magnetism and Kondo-type Ce-spin fluctuations. As x increases, the system varies gradually from a Ce mixed-valent system with 3d-host antiferromagnetism (at x=0) to a nearly trivalent system with strong 3d-host ferromagnetism (near x=1). In the antiferromagnetic (AF) phase region (0≤x≤0.5), the Neel temperature TN decreases with the increase of x, manifesting the weakening of the host AF field. Impurity Kondo behavior is observed at x=0.05, indicating that the low-temperature coherence state in CeMn2Si2 can be destroyed by "Kondo holes" which are created by very small substitution of La for Ce. The susceptibility and resistivity results suggest that the impurity Kondo effect in the 0.1 ≤ x ≤ 0.5 samples is partially suppressed by a nonvanishing ferromagnetic (FM) field component; whereas the phononlike behavior of the resistivity curves in the Mn-host FM-phase region (0.5 < x ≤ 1.0) supports our previous proposal that the Kondo-type Ce-spin fluctuations can be effectively quenched by a strong 3d-host FM field.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)