Studies of alloying effects on URu2(Si,X)2; X=Al or Ge

Abstract
We have studied alloying effects of Al and Ge on the Si site of URu2Si2 using resistivity and magnetization measurements. In contrast to previous studies of substitutions on the U and Ru sites, we observe that the substitutions of Al or Ge produce only a simple dilution effect on the itinerant antiferromagnetism transition at 17.5 K in URu2Si2. We discuss the alloying effects on TN, and in particular resistivity, in terms of d-f and sp-f hybridization.