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

Kazutaka Kudo; Keita Iba; Masaya Takasuga; Yutaka Kitahama; Jun-ichi Matsumura; Masataka Danura; Yoshio Nogami; Minoru Nohara

doi:10.1038/srep01478

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

Sci Rep. 2013:3:1478. doi: 10.1038/srep01478.

Authors

Kazutaka Kudo¹, Keita Iba, Masaya Takasuga, Yutaka Kitahama, Jun-ichi Matsumura, Masataka Danura, Yoshio Nogami, Minoru Nohara

Affiliation

¹ Department of Physics, Okayama University, Okayama 700-8530, Japan. kudo@science.okayama-u.ac.jp

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 ≤ x ≤ 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.