A comparison of the superconducting states of Ta4Pd3Te16 and Nb3PdxSe7

We have measured the superconducting upper critical fields of a Ta$_{4}$Pd$_{3}$Te$_{16}$ sample and a Nb$_{3}$Pd$_{x}$Se$_{7}$ sample with very close values of $T_{c}$. The Maki parameter of Ta$_{4}$Pd$_{3}$Te$_{16}$ ($H_{c2}(T \rightarrow 0 \, \mathrm{K}) \sim 5.5 T$) is small and hence it is an orbital limited system. However, $H_{c2}$ shows an unconventional linear $T$ dependence in the whole temperature range. Even though they have similar crystalline structures, the upper critical fields of Nb$_{3}$Pd$_{x}$Se$_{7}$ are extremely high ($H_{c2}(T \rightarrow 0 \, \mathrm{K}) \sim 25 T$) and much more anisotropic.