Superconducting Stiffness and Coherence Length of FeSe0.5Te0.5 Measured in a Zero-Applied Field

Amotz Peri, Itay Mangel, Amit Keren

Research output: Contribution to journalArticlepeer-review


Superconducting stiffness (Formula presented.) and coherence length (Formula presented.) are usually determined by measuring the penetration depth (Formula presented.) of a magnetic field and the upper critical field (Formula presented.) of a superconductor (SC), respectively. However, in magnetic SC, which is iron-based, this could lead to erroneous results, since the internal field could be very different from the applied one. To overcome this problem in Fe (Formula presented.) Se (Formula presented.) Te (Formula presented.) with (Formula presented.) and (Formula presented.) (FST), we measured both quantities with the Stiffnessometer technique. In this technique, one applies a rotor-free vector potential (Formula presented.) to a superconducting ring and measures the current density (Formula presented.) via the ring’s magnetic moment (Formula presented.). (Formula presented.) and (Formula presented.) are determined from London’s equation, (Formula presented.), and its range of validity. This method is particularly accurate at temperatures close to the critical temperature (Formula presented.). We find weaker (Formula presented.) and longer (Formula presented.) than existing literature reports, and critical exponents which agree better with expectations based on the Ginzburg–Landau theory.

Original languageEnglish
Article number39
JournalCondensed Matter
Issue number2
StatePublished - Jun 2023


  • FeSeTe
  • coherence length
  • iron-based superconductors
  • magnetism
  • stiffness
  • superconductivity

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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