Variation of the heavy fermion ground state in CeCu2Si2 crystals by stoichiometry control
Published Web Locationhttps://doi.org/10.1016/0304-8853(85)90353-1
To gain into the formation of the heavy Fermion state in CeCu2Si2 we have studied the relationship between the high temperature and low temperature physical properties. The single crystals are grown from metallic solvents, such as Sn, In or Ga. The low temperature susceptibility χ can be varied by factors of 5, and samples with smallest χ have the largest linear contribution γ to the specific heat. This "anticorrelation" of χ and γ is unexpected. The reduction of χ at low T is mainly due to a temperature independent antiferromagnetic molecular-field type interaction χ-1(T)=χ-10(T)+λ, and not due to interactions which become dominant below a characteristic temperature. Superconductivity occurs in small χ - large γ samples. © 1985.