Lattice disorder and size-induced kondo behavior in CeAl2 and CePt2+x

When the size of CeAl2 and CePt2+x particles is reduced to the nanometer scale, antiferromagnetism is suppressed and Kondo behavior predominates, with the Kondo temperature TK either decreasing (CeAl2) or increasing (CePt2+x) relative to the bulk. Local structure measurements show that these nanoparticles are significantly distorted. While such distortions should strongly affect magnetic and electronic properties, we find they cannot explain the observed changes in TK. Other size-induced changes to the electronic structure must, therefore, play a significant role.