Investigation of magnetic order in Sm${Tr}$$_2$Zn$_{20}$ (${Tr}$ = Fe, Co, Ru) and Sm${Tr}$$_2$Cd$_{20}$ (${Tr}$ = Ni, Pd)

Single crystals of the cage compounds Sm${Tr}$$_2$Zn$_{20}$ (${Tr}$ = Fe, Co, Ru) and Sm${Tr}$$_2$Cd$_{20}$ (${Tr}$ = Ni, Pd) have been investigated by means of electrical resistivity, magnetization, and specific heat measurements. The compounds SmFe$_{2}$Zn$_{20}$, SmRu$_{2}$Zn$_{20}$, and SmNi$_{2}$Cd$_{20}$ exhibit ferromagnetic order with Curie temperatures of $T_C$ = 47.4 K, 7.6 K, and 7.5 K, respectively, whereas SmPd$_{2}$Cd$_{20}$ is an antiferromagnet with a N\'{e}el temperature of $T_N$ = 3.4 K. No evidence for magnetic order is observed in SmCo$_{2}$Zn$_{20}$ down to 110 mK. The Sommerfeld coefficients $\gamma$ are found to be 57 mJ/mol-K$^2$ for SmFe$_{2}$Zn$_{20}$, 79.5 mJ/mol-K$^2$ for SmCo$_{2}$Zn$_{20}$, 258 mJ/mol-K$^2$ for SmRu$_{2}$Zn$_{20}$, 165 mJ/mol-K$^2$ for SmNi$_{2}$Cd$_{20}$, and 208 mJ/mol-K$^2$ for SmPd$_{2}$Cd$_{20}$. Enhanced values of Sommerfeld coefficients $\gamma$ and a quadratic temperature dependence of the electrical resistivity at low temperature for SmRu$_{2}$Zn$_{20}$ and SmPd$_{2}$Cd$_{20}$ suggest an enhancement of the quasiparticle masses due to hybridization between localized 4$f$ and conduction electron states.