Probing the localized to itinerant behavior of the 4f electron in CeIn3-xSnx by Gd3+ electron spin resonance

The CeIn3-xSnx 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_c ~ 0.65. In the vicinity of T_N -> 0 the system shows non-Fermi liquid behavior due to antiferromagnetic critical fluctuations. For a high Sn content, x > 2.2, 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.Comment: 9 pages, 7 figure

Electron spin resonance study of the LaIn3-xSnx superconducting system

The LaIn3-xSnx alloy system is composed of superconducting Pauli paramagnets. For LaIn3 the superconducting critical temperature T_c is approximately 0.7 K and it shows an oscillatory dependence as a function of Sn substitution, presenting its highest value T_c ~ 6.4 K for the LaSn3 end member. The superconducting state of these materials was characterized as being of the conventional type. We report our results for Gd3+ electron spin resonance (ESR) measurements in the LaIn3-xSnx compounds as a function of x. We show that the effective exchange interaction parameter J_fs between the Gd3+ 4f local moment and the s-like conduction electrons is almost unchanged by Sn substitution and observe microscopically that LaSn3 is a conventional superconductor.Comment: 9 pages, 4 figures. Replaced with the published version and updated the bibliographic informatio