Suppression of ferromagnetism in solid solution CePd_xGa_4−x

In order to extend our knowledge on effects of substitution of gallium by transition metal in solid solutions of gallides with the tetragonal BaAl₄-type crystal structure we studied physical properties of polycrystalline samples of CePd_xGa_4−x (x = 0.2−0.8). X-ray diffraction confirmed that the unit-cell volume of the system changes in a non-monotonic way with a maximum around x^∗ = 0.6. We performed magnetization, specific heat, electrical resistivity and thermoelectric power measurements in wide temperature and magnetic field ranges. Magnetic moments of Ce³⁺ ions are very close to the value corresponding to the localized 4f-state in the whole x-range covered, yet their variation with x coincides with that of lattice parameters, with a minimum close to x^∗. The alloys order ferromagnetically at low temperatures, which causes distinct anomalies of the measured properties. The ordering temperature decreases with increasing the Pd content from 3.7 K for x = 0.2 down to 1.3 K for x = 0.8. The results suggest that no quantum critical transition can be approached within the solid solution existence range. - Highlights: • CePd_xGa_4−x is a solid solution with pelectron atoms (Ga) swapped for d-electron ones (Pd). • Swapping modifies in the strength of f−(p,d)hybridization. • Magnetic, thermodynamic and electron transport properties are determined at low temperatures. • CePd_xGa_4−x adopt magnetic order in whole range of existence of the solution. • No quantum critical transition can be approached within the solid solution existence range