Transport and thermodynamic properties of (Ca 1 − x La x ) 10 (Pt 3 As 8 )(Fe 2 As 2 ) 5 superconductors

Single crystals of (Ca${}_{1\ensuremath{-}x}$La${}_{x}$)${}_{10}$(Pt${}_{3}$As${}_{8}$)(Fe${}_{2}$As${}_{2}$)${}_{5}$ ($x=0$\char21{}0.182) superconductors have been grown and characterized by x-ray, microprobe, transport, and thermodynamic measurements. Features in the magnetic susceptibility, specific heat, and two kinks in the derivative of the electrical resistivity around 100 K in the $x=0$ compound support the existence of decoupled structural and magnetic phase transitions. With La doping, the structural/magnetic phase transitions are suppressed and a half dome of superconductivity with a maximal ${T}_{c}$ around 26 K is observed in the temperature-concentration phase diagram.