Magnetization density in URu2Si2 and URh2Si2

The magnetic properties of the isostructural compounds URu2Si2 and URh2Si2 are compared in order to ascertain the different role played by Ru vs Rh. The total magnetic moment, obtained by spin‐polarized electronic calculations with the full potential augmented plane‐wave method within local spin‐density approximation, agrees quite satisfactorily with the measured one in URh2Si2, whereas it is orders of magnitude too big in URu2Si2. However, important differences are found among the two compounds: These are the substantial contribution to the total magnetic moment of negative d spin polarization and the larger radial extention and asphericity of the magnetization density (in two crystal planes) in the Ru compound compared to the Rh compound. Also, the f positive spin‐polarization density on U differs in the two compounds. This should result in different magnetic form factors in diffraction experiments.