Loading…
Unusual superconducting state at 49 K in electron-doped CaFe₂As₂ at ambient pressure
We report the detection of unusual superconductivity up to 49 K in single crystalline CaFe₂As₂ via electron-doping by partial replacement of Ca by rare-earth. The superconducting transition observed suggests the possible existence of two phases: one starting at 49 K, which has a low critical field &...
Saved in:
Published in: | Proceedings of the National Academy of Sciences - PNAS 2011-09, Vol.108 (38), p.15705-15709 |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | We report the detection of unusual superconductivity up to 49 K in single crystalline CaFe₂As₂ via electron-doping by partial replacement of Ca by rare-earth. The superconducting transition observed suggests the possible existence of two phases: one starting at 49 K, which has a low critical field < 4 Oe, and the other at 21 K, with a much higher critical field > 5 T. Our observations are in strong contrast to previous reports of doping or pressurizing layered compounds AeFe₂As₂ (or Ae122), where Ae = Ca, Sr, or Ba. In Ae122, hole-doping has been previously observed to generate superconductivity with a transition temperature (Tc) only up to 38 K and pressurization has been reported to produce superconductivity with a Tc up to 30 K. The unusual 49 K phase detected will be discussed. |
---|---|
ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.1112150108 |