Low-temperature magnetic behavior of the rare-earth cobaltites GdCoO3 and SmCoO3

The temperature and magnetic field dependences of the static magnetization of the polycrystalline rare-earth cobaltites GdCoO3 and SmCoO3 have been measured. It is shown that, below room temperature, the magnetization of both compounds derives primarily from the rare-earth ion paramagnetism. The GdCoO3 and SmCoO3 compounds have been found to differ substantially in magnetic behavior, which can be traced to differences in their electronic shell structures. The magnetic behavior of GdCoO3 is close to that of an array of free Gd3+ ions, whereas in SmCoO3 the deviation from the free-ion properties is very large because of the Sm3+ ground state being crystal-field split. Van Vleck magnetic susceptibility measurements of SmCoO3 suggest that the splitting is similar to 10 K.