Breakdown of Chemical Scaling for Pt-Doped CaFe2As2

We report a breakdown of the scaling of the antiferromagnetic transition temperature T_N on chemical doping for Pt-doped CaFe2As2. The substitution of Pt is ineffective in the reduction of antiferromagnetic ordering as well as in inducing superconductivity in Ca(Fe1-xPtx)2As2. The Pt-doped CaFe2As2 that does not exhibit superconductivity will, however, provide us an ideal opportunity to elucidate the role of chemical doping in the occurrence of superconductivity in iron-based materials.Comment: 7 pages, 2 figure

Emergence of superconductivity at 45 K by lanthanum and phosphorus co-doping of CaFe2As2

Co-doping of lanthanum and phosphorus in CaFe2As2 induces superconductivity at 45 K. This superconducting transition temperature is higher than the 38 K transition in Ba1-xKxFe2As2, which is the maximum found thus far among the 122 phases. Superconductivity with a substantial shielding volume fraction was observed at 0.12 $\leq$ x $\leq$ 0.18 and y = 0.06 in Ca1-xLaxFe2(As1-yPy)2. The superconducting phase of the present system seems to be not adjacent to an antiferromagnetic phase.Comment: 13 pages, 4 figure