Structural and magnetic phase transitions in triclinic   Ca10(FeAs)10(Pt3As8)
  We report the structural and magnetic phase transitions of triclinic Ca10(FeAs)10(Pt3As8). High-resolution X-ray powder diffraction reveals splitting of the in-plane (a,b) lattice parameters at Ts ~ 120 K. Platinum-doping weakens the distortion and shifts the transition temperature to 80 K in Ca10(Fe1-xPt_xAs)10(Pt3As8) with x = 0.03. muSR experiments show the onset of magnetic order near Ts and a broad magnetic phase transition. No symmetry breaking is associated to the structural transition in Ca10(FeAs)10(Pt3As8) in contrast to the other parent compounds of iron arsenide superconductors. 
T. St\"urzer, G. M. Friederichs, H. Luetkens, A. Amato, H.-H. Klauss,   F. Winter, R. P\"ottgen, and D. Johrendt
cond-mat.supr-con cond-mat.str-el