Magneto-optical imaging and transport properties of FeSe superconducting tapes prepared by the diffusion method

Ding, Qing-Ping; Mohan, Shyam; Tsuchiya, Yuji; Taen, Toshihiro; Nakajima, Yasuyuki; Tamegai, T.

doi:10.1088/0953-2048/25/2/025003

Cited by 34 publications

(28 citation statements)

References 21 publications

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“…These images clearly illustrate that a macroscopic superconducting current is able to circulate in the entire sample surface and effectively screen the applied external field. This behavior contrasts with the field penetration in polycrystalline FeSe tapes, where a considerable distribution of T c and weak-link features has been reported 30 . In the third column in Fig.…”

Section: Resultscontrasting

confidence: 59%

Impurity scattering effects on the superconducting properties and the tetragonal-to-orthorhombic phase transition in FeSe

Abdel-Hafiez

Brisbois

et al. 2016

Phys. Rev. B

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A comprehensive study of the doping dependence phase diagram of FeSe-based superconductors is still required due to the lack of a clean and systematic means of doping control. Here, we report on the magneto-optical imaging, thermodynamic and transport properties, as well as in-situ angleresolved photoemission spectroscopy (ARPES) studies, on the impurity scattering in stoichiometric FeSe single crystals. Co doping at the Fe site, is found to decrease the superconducting transition temperature (Tc). The upper critical field and specific heat all indicate a possible multiband with strong coupling superconductivity in the Co-doped system. A remarkable feature in FeSe is that its temperature dependent resistivity exhibits a wide hump at high temperatures, signature of a crossover from a semiconducting-like behavior to metallic behavior. ARPES data between 180 K and 282 K indicates the existence of chemical potential shift with increasing thermal excitations, resulting in a change of the Fermi surface topology and exhibiting a semi-metal behavior. We found that the temperature induced-Lifshitz transition is much higher than the temperature for the nematic order. A structural tetragonal-to-orthorhombic phase transition (Ts) (consequence of the electronic nematicity) is suppressed by either physical or chemical pressures. Due to the reconstruction of the Fermi surface at Ts, specific heat anomalies at Ts present ∆Cp/Ts ≈ γn, the Sommerfield coefficient at low temperature. This reflects additional electronic instability in the FeSe1−xSx system.

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Section: Resultscontrasting

confidence: 59%

Impurity scattering effects on the superconducting properties and the tetragonal-to-orthorhombic phase transition in FeSe

Abdel-Hafiez

Brisbois

et al. 2016

Phys. Rev. B

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“…This technique shows visually the position of cracks [5,8], weak links [4,6,7] and other micro-and macroscopic defects in the sample [2,9], however there may be other current-limiting mechanisms that are not so readily visible at the macroscopic scale nor directly dependent on critical current density [10,11].…”

Section: Introductionmentioning

confidence: 99%

Dynamic magneto-optical imaging of superconducting thin films

Wells

Pan

Wilson

et al. 2016

Supercond. Sci. Technol.

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We present a novel method for analysis of superconducting thin films using dynamic magneto-optical imaging, revealing hallmarks of flux penetration with temporal resolution around 1 ms (in the present work) or better. This method involves investigation of transient field and dynamic current distributions, which are calculated by an inversion procedure on the Biot-Savart Law, which we show to be valid under dynamic conditions. We compare and discuss the flux front penetration speed and evolution of current distribution in high quality YBa2Cu3O${}_{7-\delta }$ thin films with that of samples deliberately damaged in such a way as to reduce critical current density without causing macroscopic damage. We present a novel method for analysis of superconducting thin films using dynamic magnetooptical imaging, revealing hallmarks of flux penetration with temporal resolution around 1 ms (in the present work) or better. This method involves investigation of transient field and dynamic current distributions, which are calculated by an inversion procedure on the Biot-Savart Law, which we show to be valid under dynamic conditions. We compare and discuss the flux front penetration speed and evolution of current distribution in high quality YBa2Cu3O7−δ thin films with that of samples deliberately damaged in such a way as to reduce critical current density without causing macroscopic damage.

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“…In basic research field, single-layer FeSe films have been successfully synthesized, with the surprisingly increased T c to ∼65 K [6] , which provides an opportunity to study the formation mechanism of superconductivity. Meanwhile, FeSe can be made into superconducting wires and tapes for practical applications under low temperature and high magnetic field [7,8] . In addition, the T c of FeSe system can also be improved to 15 K by Te or S substitution at Se site, and to 37 K via the application of external pressure [9,10] .…”

Section: Introductionmentioning

confidence: 99%