Collective heavy-fermion state and superconductivity in Pr1−xLaxOs4Sb12: A specific heat study

C. R. Rotundu; P. Kumar; B. Andraka

doi:10.1103/PhysRevB.73.014515

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Collective heavy-fermion state and superconductivity in Pr1−xLaxOs4Sb12: A specific heat study

C. R. Rotundu, P. Kumar, B. Andraka

DOI 10.1103/PhysRevB.73.014515 · Physical Review B

T1

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Abstract

We report the low-temperature susceptibility and specific heat for single crystals of Pr1−xLaxOs4Sb12(0⩽x⩽1). The ionic properties of the material, characterized by the energy spectrum of crystalline electric field (CEF) levels of Pr, are unchanged by La doping. The average Tc is only weakly affected by La substitution and varies approximately linearly between the end compounds. The discontinuity in the specific heat divided by temperature C∕T at Tc is drastically reduced from about 800mJ∕K2mol for x=0 to the value of LaOs4Sb12 near x=0.3. This behavior of a superconducting transition implies a collective origin of the heavy-fermion state in PrOs4Sb12. We suggest that fluctuations of the anti-ferro-quadrupolar order parameter are responsible for this heavy-fermion state.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
PrOs4Sb12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
LaOs4Sb12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	0.74	Pressure not reported	onset
Pr1-xLaxOs4Sb12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown