Inhomogeneous Superconducting Behaviour in $$\hbox {La}_{5}\hbox {Ni}_{2}\hbox {Si}_{3}$$ La 5 Ni 2

Abstract

The superconducting phase transition at T c = 2.3 K was observed for the electrical resistivity ρ(T ) and magnetic susceptibility χ(T ) measurements in the ternary compound La 5 Ni 2 Si 3 that crystallizes in the hexagonal-type structure. Although a single-phase character with the nominal stoichiometry of the synthesized sample was confirmed, a small trace of the La-Ni phase was found, being probably responsible for the superconducting behaviour in the investigated compound. The magnetization loop recorded at T = 0.5 K resembles a star-like shape which indicates that the density of the critical current can be strongly suppressed by a magnetic field. The low-T ρ (T ) and specific heat C p (T ) data in the normal state reveal simple metallic behaviour. No clear evidence of a phase transition to any long-or short-range order was found for C p (T ) measurements in the T -range of 0.4-300 K.