Magnetic properties of CexY1-xPt compared to CexLa1-xPt ones

We have investigated the magnetic properties of the CexY1-xPt Kondo ferromagnetic alloy system in the temperature range from 1.8 K to 320 K. The results of these investigations can be summarized as follows: dc-susceptibility can be described by the Curie-Weiss law at higher temperatures down to about 100 K, but also at low temperatures above the ferromagnetic phase transition. At higher temperatures, the extracted Curie-Weiss parameter, θp, is negative and at low temperature θC is positive. The extracted effective magnetic moment above 100 K increases with the Ce content up to almost the theoretical value of the isolated Ce3+ ion, μ = 2.54 μB, for CePt. This suggests an increase of the hybridization with decreasing Ce content, or said equivalently, it means that the increase of the Kondo interaction diminishes effective magnetic moment. These observations confirm the main conclusions inferred from an earlier transport properties investigation of this alloy system. The corresponding θC differs within 1 K from the Curie temperature, TC, which is determined by the resistivity measurements. The most intriguing result of the investigation of CexY1-xPt is the linear concentration dependence of TC vs. x and, moreover, it is the same as in CexLa1-xPt although in the former system the hybridization diminishes considerably the effective magnetic moment per Ce ion, while in the latter system, hybridization is minor and independent of x. We offer the explanations of these intriguing experimental results.