Magnetic behavior of single-crystal Ho 2 PdSi 3

The magnetic behavior of single-crystal ${\mathrm{Ho}}_{2}{\mathrm{PdSi}}_{3},$ crystallizing in an ${\mathrm{AlB}}_{2}$-derived hexagonal structure, is investigated by magnetic susceptibility $(\ensuremath{\chi})$ and electrical resistivity $(\ensuremath{\rho})$ measurements along two directions. There is no dramatic anisotropy in the high-temperature Curie-Weiss parameter or in the $\ensuremath{\rho}$ and isothermal magnetization data, though there is a noticeable anisotropy in the magnitude of $\ensuremath{\rho}$ between two perpendicular orientations. The degree of anisotropy is overall less prominent than in the Gd (which is an S-state ion) and Tb analogs. A point of emphasis is that this compound undergoes long-range magnetic ordering below 8 K as in the case of analogous Gd and Dy compounds. Considering this fact for these compounds with a well-localized f orbital, the spin-glass freezing noted for isomorphous U compounds in the recent literature could be attributed to the role of the f-ligand hybridization, rather than just Pd-Si disorder.