Magnetic behavior of the alloys CeCu yGa 4− y and Ce 1− xLa xCuGa 3

Abstract

The results of magnetic susceptibility ( x), electrical resistivity (ρ) and heat-capacity ( C) measurements of the alloys CeCu y Ga 4− y ( y = 0.5, 1.0, 1.25 and 1.5) and Ce 1− x La x CuGa 3 ( x = 0.2 and 0.9), crystallizing in the BaAl 4-type tetragonal structure, are reported. The Kondo effect tends to dominate with increasing y. All the data for the y = 0.5 alloy are consistent with the onset of ferromagnetic ordering at 6 K. For y = 1.0 and 1.25, though ρ gradually drops below 6 K, the C data do not show the existence of magnetic ordering above 2 K; presumably, for y = 1.0, 1.25 and 1.5, long-range magnetic ordering sets in below 2 K. Above all, C tends to increase with decreasing temperature before the onset of long range magnetic ordering and the values of C/ T per Ce mol are considerably diminished for x = 0.9. It is proposed that this C/ T enhancement lies in the magnetic precursor effects and not on the heavy-fermion behaviour.