Development of crystal structure and magnetism in RCuAl3−xGax solid solutions (R = Ce, La).

We present the study of structural and electronic properties in tetragonal R CuAl 3− x Ga x solid solutions (where R = Ce, La), based on X-ray diffraction, magnetization, ac-susceptibility, specific heat and electrical resistivity measurements. The development of lattice parameters with Ga content shows a clear change between concentrations with x < 1 and x > 1. All studied materials order magnetically with the ordering temperature around 2 K. The specific heat analysis leads to estimation of the energy splitting between the ground state and the first excited crystal field level. The splitting increases with increasing Ga content. The magnetoresistance measurements reveal strong ferromagnetic correlations in paramagnetic state, at least in Ga rich part of the series. [ABSTRACT FROM AUTHOR]