Ferromagnetic CeSi1.2Ga0.8 alloy: Study on magnetocaloric and thermoelectric properties

Abstract

We present the magnetic, specific heat, electrical resistivity, and thermoelectric power measurements for the intermetallic compound CeSi1.2Ga0.8. This composition belongs to the series CeSi2-xGax, which exhibits diverse magnetic orderings and different crystallographic structures depending on the substitution level x. It has been previously suggested that for 0.0 < x < 1.3 the compounds crystallize in the alpha-ThSi2 type structure and for 0.7 < x < 1.3 they order ferromagnetically below 14 K. Our complementary studies for x = 0.8 reveal that it is a complex system due to the Kondo scattering competing with the RKKY interactions. The transition from the paramagnetic to the ferromagnetic state takes place at T-C = 12.5(1) K. Moreover, the Seebeck coefficient and electrical resistivity show not only an anomaly related to the magnetic transition, but also a broad maximum at-90 K related to the crystal field effect. The case of x = 0.8 is of special interest as it is at the crossing of the characteristic temperatures, i.e. T-ord (magnetic ordering temperature)similar to & nbsp; T-K (Kondo temperature) similar to 10 K. Additionally, ab initio electronic structure calculations were performed allowing us to determine phase stability, (revealing two stable phases -alpha-GdSi2-type and alpha-ThSi2-type structures) as well as spin and orbital moment decomposition on Ce-states for both considered structures.