Chemical pressure and magnetic field effects in CePtGa

Abstract

The antiferromagnetic Kondo compound CePtGa and the Ce(Pt1−xNix)Ga and CePt(Ga1−yAly) alloy systems have been studied by resistivity ρ(T), magnetoresistivity MR and susceptibility χ(T) measurements on polycrystalline samples to temperatures as low as 1.5 K and in magnetic fields up to 9 T. A Doniach diagram is presented of the volume dependences of the Néel temperature TN and Kondo temperature TK of these alloys and the possible existence of a quantum critical point near x = 0.38 is indicated. χ(T) measurements in different applied fields indicate a marked decrease in TN with field for the parent CePtGa compound and extrapolation of the results suggests that magnetic order should disappear in a field of 4.8 T. In contrast the Kondo energy scale, identified by a maximum in ρ(T) at low temperatures, increases significantly with field.