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Title: Probing chiral superconductivity in Sr 2RuO 4 underneath the surface by point contact measurements

Sr2RuO4 (SRO) is the prime candidate for a chiral p-wave superconductor with critical temperature $${T}_{{\rm{c}}}(\mathrm{SRO})\sim 1.5$$ K. Chiral domains with opposite chiralities $${p}_{x}\pm {{\rm{i}}{p}}_{y}$$ have been proposed, but are yet to be confirmed. We measure the field dependence of the point contact (PC) resistance between a tungsten tip and an SRO–Ru eutectic crystal, where micrometer-sized Ru inclusions are embedded in SRO with an atomically sharp interface. Ruthenium is an s-wave superconductor with $${T}_{{\rm{c}}}(\mathrm{Ru})\sim 0.5$$ K; flux pinned near the Ru inclusions can suppress its superconductivity, as reflected in the PC resistance and spectra. This flux pinning effect originates from SRO underneath the surface and is very strong once flux is introduced. To fully remove flux pinning, one needs to thermally cycle the sample above T c(SRO) or apply alternating fields with decreasing amplitude. With alternating fields, the observed hysteresis in magnetoresistance can be explained by domain dynamics, providing support for the existence of chiral domains. The origin of the strong pinning could be the chiral domains themselves.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [3] ; ORCiD logo [1]
  1. Peking Univ., Beijing (China). School of Physics, International Center for Quantum Materials; Collaborative Innovation Center for Quantum Matter, Beijing (China)
  2. Tulane Univ., New Orleans, LA (United States). Dept. of Physics
  3. Pennsylvania State Univ., University Park, PA (United States). Dept. of Physics and Materials Research Inst.; Shanghai Jiao Tong Univ. (China). Dept of Physics and Astronomy and Key Lab. of Artificial Structures and Quantum Control
Publication Date:
Grant/Contract Number:
SC0012432; FG02-04ER46159; 2012CB927400; 2012CB927403
Type:
Published Article
Journal Name:
New Journal of Physics
Additional Journal Information:
Journal Volume: 19; Journal Issue: 5; Journal ID: ISSN 1367-2630
Publisher:
IOP Publishing
Research Org:
Tulane Univ., New Orleans, LA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1437703
Alternate Identifier(s):
OSTI ID: 1393550