CePdSb: A possible ferromagnetic Kondo-lattice system

Abstract

Magnetic-susceptibility and electrical-resistivity measurements on CePdSb and GdPdSb have been carried out in the temperature range of 4.2–300 K. The measurements reveal that CePdSb orders ferromagnetically with an ordering temperature (${\mathit{T}}_{\mathit{M}}$) of 17 K while GdPdSb orders antiferromagnetically with a Néel temperature (${\mathit{T}}_{\mathit{N}}$) of 15.5 K. In the paramagnetic state, the susceptibility of CePdSb follows Curie-Weiss behavior between 50 and 300 K but deviates from it below 50 K. Its saturation magnetic moment per formula unit at 4.2 K is 1.2${\mathrm{\mu }}_{\mathit{B}}$, which is reduced from the free-ion value of 2.14${\mathrm{\mu }}_{\mathit{B}}$ for the ${\mathrm{Ce}}^{3+}$ ion. The resistivity of CePdSb shows a broad maximum at about 150 K and a ln(T) behavior at high temperatures, indicating the combined influence of crystalline electric fields and Kondo effect on the 4f moments. Thus CePdSb appears to be a Kondo-lattice system with ferromagnetic ordering of the cerium moments.