Disorder and size effects in Kondo lattice nanoparticles

The evolution of Kondo interactions and magnetic order with size variation was revealed by the specific heat and magnetic susceptibility in a series of CePt$_{2}$ Kondo lattice nanoparticles with various sizes. In addition to the magnetic order suppression with size reduction, two regimes of size dependence of Kondo temperature T$_{K}$ was observed. As size d decreases from the bulk down to 22 nm firstly T$_{K}$ slightly decreases from 4.6 K to 3.7 K, as d further decreases, inversely T$_{K}$ increases up to 100 K for size d=3.8 nm. It is confirmed that the size-induced lattice disorders are responsible for the result for d $\ge $ 22 nm, while the rapid increase of T$_{K}$ for d =3.8 nm is attributed to the lattice contraction and quantum size effects.