CeRh3B2:A ferromagnet with anomalously large Ce5dspin and orbital magnetic moments

We report a high-energy magnetic-Compton-scattering study performed on the ferromagnet ${\mathrm{CeRh}}_3{\mathrm{B}}_2.$ This technique solely measures the electron spin magnetic moments. In contrast to a number of Ce intermetallics with nonmagnetic elements, the Ce $5d$ spin moment is found to be large and parallel to the Ce $4f$ spin moment. Therefore the Kondo effect does not play a key role for ${\mathrm{CeRh}}_3{\mathrm{B}}_2.$ The inferred large Ce $5d$ orbital magnetic moment is a signature of the strong spin-orbit interaction for the Ce $5d$ band.