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

TL;DR

This study demonstrates that co-doping CaFe2As2 with lanthanum and phosphorus induces superconductivity at 45 K, surpassing previous maximum transition temperatures in similar 122-phase materials.

Contribution

It reports the discovery of high-temperature superconductivity at 45 K in co-doped CaFe2As2, a significant improvement over prior 38 K limits in related compounds.

Findings

Superconductivity at 45 K achieved in co-doped CaFe2As2.

Superconductivity observed with substantial shielding volume fraction.

Superconducting phase not adjacent to antiferromagnetic phase.

Abstract

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.