title: Investigation of the heavy fermion state and superconductivity in Pr(1-x)La(x)Os4Sb12 by the upper critical field slope at Tc.
abstract: Measurements of the upper critical field H(c2) near T(c) of Pr(1 - x)La(x)Os(4)Sb(12) were performed by specific heat. The results support the hypothesis of a non-single-ion origin of m* enhancement in PrOs(4)Sb(12), derived from the analysis of the C/T discontinuity at T(c). Both sets of measurements indicate the existence of a crossover concentration, x(cr)≈0.2-0.3, separating heavy fermion-like alloys (x < x(cr)) from normal metals (x > x(cr)). Heavy fermion-like alloys exhibit field-induced long-range antiferro-quadrupolar (AFQ) anomalies in the specific heat, while those with x > x(cr) do not. The curvature in H(c2) versus T near T(c), observed in different measurements on pure PrOs(4)Sb(12), is sample- and method-dependent.
authors.affiliation: Department of Physics, University of Florida, Gainesville, FL 32611-8440, USA. andraka@phys.ufl.edu
authors.forename: B
authors.initials: B
authors.lastname: Andraka
authors.forename: C R
authors.initials: CR
authors.lastname: Rotundu
authors.forename: P
authors.initials: P
authors.lastname: Kumar
authors.forename: H
authors.initials: H
authors.lastname: Tsujii