Single-Site and Inter-Site Effects in Heavy Fermion Compound CeRu2Si2Studied by Constant Volume Dilution

Abstract

In order to study the single-site and inter-site effects in CeRu 2 Si 2 , a systematic diluting experiment has been performed with the single crystals of pseudo-ternary alloys Ce 1- x (La 0.63 Y 0.37 ) x Ru 2 Si 2 [0≤ x ≤1], where the unit cell volume is kept unchanged to avoid the chemical pressure effect. Magnetization process in fields H ≤200 kOe and at applied pressures P ≤5 kbar, specific heat C ( T ), electrical resistivity ρ( T ) and thermal expansion have been measured at temperatures above 1.5 K, with a special attention being paid to the metamagnetic behavior inherent in CeRu 2 Si 2 . In a whole Ce concentration range, the system remains in a non-magnetic state. Sharp metamagnetism shows a rapid broadening with x , and disappears at x ∼0.2 where incoherent Kondo scattering becomes significant in ρ( T ). By careful analysis of single-site contributions, a peak structure is revealed in C ( T ) which is not explained by the “Kondo peak” alone. The result can be interpreted by a pseudo-gap in the qu...