Field-Independent Features in the Magnetization and Specific Heat of Sm₃Co₄Ge₁₃

Abstract

The cubic intermetallic compound Sm 3Co 4Ge 13 (space group P m 3 ¯ n ) possesses a cage-like structure composed of Ge and displays an antiferromagnetic transition at T N ≈ 6 K in magnetization, M ( T ) , specific heat, C p ( T ) and in thermal conductivity, κ ( T ). The magnetic transition at T N is observed to be robust against applied magnetic fields up to 9 T. From the analysis of specific heat, a Sommerfeld coefficient γ = 80(2) mJ/mol-Sm K 2 is estimated. The magnetic entropy released at T N is estimated as lower than that of a doublet, R ln(2). A positive Seebeck coefficient is observed for the thermopower, S ( T ) . Photoemission spectroscopy reveals distinct electronic character of the near-E F valence band states arising out of Co( 3 d)-Sm( 4 f) hybridization and Sm( 4 f) electron correlation. The unusual field-independent features in magnetization, specific heat and electrical transport is an indication of the significant correlation between f and d wave functions.

Keywords

• quasi-skutterudites
• samarium
• field-insensitive