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Title: Imaging atomic-scale effects of high-energy ion irradiation on superconductivity and vortex pinning in Fe(Se,Te)

Journal Article · · Science Advances

Maximizing the sustainable supercurrent density, JC, is crucial to high-current applications of superconductivity, and to achieve this, preventing dissipative motion of quantized vortices is key. Irradiation of superconductors with highenergy heavy ions can be used to create nanoscale defects that act as deep pinning potentials for vortices. This approach holds unique promise for high-current applications of iron-based superconductors because JC amplification persists to much higher radiation doses than in cuprate superconductors without significantly altering the superconducting critical temperature. However, for these compounds, virtually nothing is known about the atomic-scale interplay of the crystal damage from the high-energy ions, the superconducting order parameter, and the vortex pinning processes. We visualize the atomic-scale effects of irradiating FeSexTe1$$-$$x with 249-MeV Au ions and find two distinct effects: compact nanometer-sized regions of crystal disruption or “columnar defects,” plus a higher density of single atomic site “point” defects probably from secondary scattering. We directly show that the superconducting order is virtually annihilated within the former but suppressed by the latter. Simultaneous atomically resolved images of the columnar crystal defects, the superconductivity, and the vortex configurations then reveal how amixed pinning landscape is created, with the strongest pinning occurring at metallic core columnar defects and secondary pinning at clusters of point-like defects, followed by collective pinning at higher fields.

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Science - Energy Frontier Research Center - Center for Emergent Superconductivity; USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division
DOE Contract Number:
AC02-06CH11357
OSTI ID:
1356974
Journal Information:
Science Advances, Vol. 1, Issue 4; ISSN 2375-2548
Publisher:
AAAS
Country of Publication:
United States
Language:
English