Electron spin resonance of Gd3+ in the antiferromagnetic heavy fermion CeIn3 and its reference compound LaIn3

Abstract

Abstract We report temperature dependent electron spin resonance (ESR) experiments of Gd 3 + in CeIn 3 and in its reference compound LaIn 3 taken in crushed single crystals. For LaIn 3 a single Dysonian Gd 3 + ESR line with a nearly temperature independent g ~ 2.020 ( 5 ) is observed, and its linewidth follows a Korringa-like behavior as a function of temperature. From the Korringa rate ( Δ H / Δ T ~ 16 Oe / K ) and g -shift ( Δ g ~ 0.027 ) we have extracted the exchange parameter between the Gd 3 + local moments and the conduction electrons (ce) in this compound. This exchange parameter J fs ≈ 20 meV was found to be ce wave-vector independent. For CeIn 3 , the Gd 3 + ESR spectra were found to be weakly temperature dependent and present partly resolved Gd 3 + fine-structure. Interestingly, for CeIn 3 , the g -shift with respect to the g -value of Gd 3 + in insulators is negative, in contrast to the positive g -shift found for Gd 3 + in LaIn 3 . These results suggests different electronic structure at the Gd 3 + site in the Kondo antiferromagnet host CeIn 3 . Possibly, Kondo effect may cause a decrease of the s -like conduction electron density of states at the Gd 3 + site, giving arise to an exchange interaction only between the Gd 3 + local moment and the Ce 4f electrons.