Heavy Fermion Behavior, Crystalline Electric Field Effects, and Weak Ferromagnetism in SmOs_{4}Sb_{12}

Abstract

The filled skutterudite compound SmOs_{4}Sb_{12} was prepared in single crystal form and characterized. The SmOs_{4}Sb_{12} crystals have the LaFe_{4}P_{12}-type structure with lattice parameter a = 9.3085 Angstroms. Specific heat measurements indicate a large electronic specific heat coefficient of ~880 mJ/mol K^{2}, from which an enhanced effective mass m^{*} ~ 170 m_{e} is estimated. The specific heat data also suggest crystalline electric field (CEF) splitting of the Sm^{3+} J = 5/2 multiplet into a Gamma_{7} doublet ground state and a Gamma_{8} quartet excited state separated by 37 K. Electrical resistivity rho(T) measurements reveal a decrease in rho(T) below ~50 K that is consistent with CEF splitting of ~33 K between a Gamma_(7) doublet ground state and Gamma_{8} quartet excited state. Specific heat and magnetic susceptibility measurements display a possible weak ferromagnetic transition at ~2.6 K, which could be an intrinsic property of SmOs_4Sb_{12} or possibly due to an unknown impurity phase.

24 pages, 11 Postscript figures, to be published in Physical Review B

References in corpus (3)

• Deviation from the Kadowaki-Woods relation in Yb-based intermediate-valent systems
• Generalized Kadowaki-Woods Relation in Heavy Fermion Systems with Orbital Degeneracy
• Crystalline electric field effects in the electrical resistivity of PrOs${}_4$Sb${}_{12}$

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