Suppression of ferromagnetism in solid solution CePdxGa4−x

Abstract

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 CePdxGa4−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.