Self-consistent perturbation theory for thermodynamics of magnetic impurity systems

Abstract

Integral equations for thermodynamic quantities are derived in the framework of the noncrossing approximation (NCA). Entropy and specific heat of 4f contribution are calculated without numerical differentiations of thermodynamic potential. The formulation is applied to systems such as PrFe 4P12 with singlet-triplet crystalline electric field (CEF) levels. © 2006 The Physical Society of Japan.