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Sample size dependent critical current density has been observed in magnesium diboride superconductors. At high fields, larger samples provide higher critical current densities, while at low fields, larger samples give rise to lower…

Superconductivity · Physics 2009-11-10 M. J. Qin , S. Keshavarzi , S. Soltanian , X. L. Wang , H. K. Liu , S. X. Dou

If the critical current density Jc is very high for a superconductor, then estimating its value from transport measurements is not very easy. In such cases, the value of Jc, called Jcm for magnetic Jc, is usually obtained from the measured…

The critical current density has been measured on single crystals of Ru substituted BaFe2As2 superconductor at several temperatures and in fields up to 16 T. The magnetisation versus field isotherms reveal the occurrence of a clear second…

Superconductivity · Physics 2012-12-03 Shilpam Sharma , K. Vinod , C. S. Sundar , A. Bharathi

The estimation of the critical current ($I_c$) and AC losses of high-temperature superconductor (HTS) devices through modeling and simulation requires the knowledge of the critical current density ($J_c$) of the superconducting material.…

Superconductivity · Physics 2017-02-01 Víctor M. R. Zermeño , Krzysztof Habelok , Mariusz Stępień , Francesco Grilli

The determination of the critical current density from magnetic hysteresis loops is widely used to characterize and compare superconducting samples. Magnetic hysteresis loops for tapes and single crystals depend on both the critical current…

Superconductivity · Physics 2025-09-05 D. M. Gokhfeld , Yu. S. Gokhfeld

The critical current density Jc in type-II conventional and high-Tc superconducting bulk materials is investigated based on the quantum theory for the vortex dynamics. It is shown that for a constant magnetic field, the critical current…

Superconductivity · Physics 2012-04-17 Ming Ju Chou , Wei Yeu Chen

This study analyzes the calculation of the critical current density Jc,mag by means of Bean's critical state model, using the equation formulated by Gyorgy et al. and other similar equations derived from it reported in the literature. While…

Superconductivity · Physics 2025-01-15 M. Polichetti , A. Galluzzi , R. Kumar , A. Goyal

Three independent components of critical current density, one for the H//c axis and the other two for the H//ab plane, have been studied in CaKFe4As4 single crystals. When the magnetic field is applied along the c axis, we observed…

A method to derive the charge current density and its quantum mechanical correlation from the scattering matrix is discussed for quantum scattering systems described by a time-dependent Hamiltonian operator. The current density and charge…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Tooru Taniguchi

We investigate the in-field critical current density Jc(B) of SNS Josephson Junctions (JJs) and polycrystalline superconductors with grain boundaries modelled as Josephson type planar defects, both analytically and through computational…

Superconductivity · Physics 2021-10-06 A. I. Blair , D. P. Hampshire

New experimental data are presented on the scan rate dependence of the magnetization hysteresis width $\Delta M(H)$ ($\propto$ critical current density $J_c(H)$) in isothermal $M-H$ scans in a weakly pinned single crystal of…

Superconductivity · Physics 2009-11-11 S. Sarkar , A. D. Thakur , C. V. Tomy , G. Balakrishnan , D. McK. Paul , S. Ramakrishnan , A. K. Grover

We determine the critical current anisotropy at maximum Lorentz force from hysteresis loops in a vibrating sample magnetometer. To eliminate the signal of spurious variable Lorentz force currents it is sufficient to cut the sample to a…

Superconductivity · Physics 2011-02-01 F. Hengstberger , M. Eisterer , H. W. Weber

We theoretically investigate the response of a superconducting film to line currents flowing in linear wires placed above the film, and we present analytic expressions for the magnetic-field and current distributions based on the critical…

Superconductivity · Physics 2009-11-11 Yasunori Mawatari , John R. Clem

Polycrystalline NdFeAsO0.88F0.12 superconductors prepared by high pressure (HP) and ambient pressure (AP) method were comparatively studied by magnetization and transport measurements. Upper critical field (Hc2), irreversibility field…

Superconductivity · Physics 2010-09-08 Y. Ding , Y. Sun , X. D. Wang , H. C. Wang , Z. X. Shi , Z. A. Ren , J. Yang , W. Lu

We present the latest generation of superconductor-insulator-ferromagnet-superconductor Josephson tunnel junctions with a step-like thickness of the ferromagnetic (F) layer. The F-layer thicknesses $d_1$ and $d_2$ in both halves were varied…

Superconductivity · Physics 2010-08-09 M. Weides , U. Peralagu , H. Kohlstedt , J. Pfeiffer , M. Kemmler , C. Gürlich , E. Goldobin , D. Koelle , R. Kleiner

We investigate the magnetic hysteresis of a superconducting microstrip resonator with a high edge barrier. We measure the magnetic hysteresis while either sweeping a magnetic field or tuning the edge barrier by high microwave current. We…

Superconductivity · Physics 2018-12-11 Sangil Kwon , Yong-Chao Tang , Hamid R. Mohebbi , David G. Cory , Guo-Xing Miao

The high-T_c glass model can be combined with the repulsive tt'--Hubbard model as microscopic description of the striped domains found in the high-T_c materials. In this picture the finite Hubbard clusters are the origin of the d-wave…

Superconductivity · Physics 2015-06-25 Ingo Morgenstern , Werner Fettes , Thomas Husslein

We analyze the influence of the magnetic field generated by the supercurrents (self-field) on the current density distribution by numerical simulations. The thickness of the superconducting film determines the self-field and consequently…

Superconductivity · Physics 2010-01-21 F. Hengstberger , M. Eisterer , H. W. Weber

Magnetic junction is considered which consists of two ferromagnetic metal layers, a thin nonmagnetic spacer in between, and nonmagnetic lead. Theory is developed of a magnetization reversal due to spin injection in the junction.…

Materials Science · Physics 2009-11-10 R. J. Elliott , E. M. Epshtein , Yu. V. Gulyaev , P. E. Zilberman

We study the dynamics of a viscoelastic medium driven through quenched disorder by expanding about mean field theory in $6-\epsilon$ dimensions. The model exhibits a critical point separating a region where the dynamics is hysteretic with a…

Condensed Matter · Physics 2009-11-07 M. Cristina Marchetti , Karin A. Dahmen