Probing the localized to itinerant behavior of the 4f electron in CeIn 3-xSn x by Gd3 + electron spin resonance

The CeIn 3-xSn x cubic heavy fermion system presents an antiferromagnetic transition at T N=10 K, for x=0, that decreases continuously down to 0 K upon Sn substitution at a critical concentration of x c0.65. In the vicinity of T N→0 the system shows non-Fermi liquid behavior due to antiferromagnetic critical fluctuations. For a high Sn content, x2.2, intermediate valence effects are present. In this work we show that Gd3 +-doped electron spin resonance (ESR) probes a change in the character of the Ce 4f electron, as a function of Sn substitution. The Gd3 + ESR results indicate a transition of the Ce 4f spin behavior from localized to itinerant. Near the quantum critical point, on the antiferromagnetic side of the magnetic phase diagram, both localized and itinerant behaviors coexist. © 2012 American Physical Society