2004/02/24 by C. R. Rotundu, P. Kumar, Rotundu, C. R. +3
Materials Science · Physics and Astronomy · #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.cond-mat/0402599
arxiv created 2004/02/24 · arxiv updated 2009/12/01
Low temperature susceptibility and specific heat for single crystals of Pr1-xLaxOs4Sb12 (0 ≤ x ≤ 1) are reported. La-doping leaves CEF energies of Pr essentially unchanged. The average Tc is only weakly affected by the La-substitution and varies approximately linearly between the end-compounds. The second superconducting transition disappears between x=0.05 and 0.1. The discontinuity in C/T at Tc, on the other hand, is drastically reduced from about 1000 mJ/K2mol for x=0 to 200 mJ/K2mol for x=0.2. ΔC/Tc decreases further for alloys corresponding to x≥ 0.6 to the value of a conventional superconductor LaOs4Sb12. This behavior implies non-single impurity origin of the heavy fermion state in PrOs4Sb12. We argue that critical quadrupolar fluctuations are responsible for this heavy fermion state.