Evolution of magnetism in Ho(Co1-xSix)2 compounds

We present results of magnetic, resistivity and dilatometric studies ofHo(Co1-xSix)2 compounds for x = 0-0.15. HoCo2 orders magnetically by a first-order transition at TC = 76 K. The associated formation of the Co moment is accompanied by a resistivity drop Δρ ∼ 70% and a sudden lattice expansion. The Si doping yields increase of TC up to 111 K for x = 0.075 while the Co moment (derived from magnetization and magnetovolume data) is reduced, Δρ is gradually diminishing and vanishes for x ≥ 0.075. Electronic structure variations due to the Si doping should be considered to understand the evolution of magnetism in the Ho(Co1-xSix)2 system. (orig.)