Evolution of ferromagnetic order in URhGe alloyed with Ru, Co and Si

We have investigated the evolution of ferromagnetic order in the correlated metal URhGe (Curie temperature TC=9.5TC=9.5 K) by chemical substitution of Ru, Co and Si. Polycrystalline samples URh1−xRuxGe (x≤0.6x≤0.6), URh1−xCoxGe (x≤0.9x≤0.9) and URhGe1−xSix (x≤0.2x≤0.2) have been prepared and the magnetic properties have been investigated by magnetization and transport experiments. In the case of Ru doping, TCTC initially increases, but then decreases linearly as a function of x   and is completely suppressed for xcr≈0.38xcr≈0.38. The Curie temperature in the URh1−xCoxGe series has a broad maximum TC=20TC=20 K near x=0.6x=0.6 and then drops to 8 K for x=0.9x=0.9. In the case of Si doping TCTC stays roughly constant. We conclude that the alloy systems URh1−xRuxGe and URh1−xCoxGe are interesting candidates to study the ferromagnetic instability.