Thermodynamic properties and magnetism of Ce₃Cu₃Sb₄

Abstract

The specific heat capacity cp(T) of Ce3Cu3Sb4 was determined between 0.6 K and 100 K in magnetic fields up to Hext = 140 kOe. The magnetic ordering transition at 10.8(1) K shows up as a tiny step-like anomaly in cp(T), while at lower temperatures a large anomaly centred at 4.8(1) K is observed. In small magnetic fields the transition shifts to higher temperature and disappears for Hext≈10 kOe. The large anomaly broadens as well and shifts to higher temperature with the increase of Hext to 140 kOe. In Arrott plots of isothermal magnetization curves M(Hext) the critical isotherm is found for Tc≈4 K. These thermodynamic data thus suggest that the evolution of magnetic order in Ce3Cu3Sb4 and related compounds is more complicated than described previously.