Enhanced Vortex Pinning and Critical Current Density in Proton-Irradiated YBa2Cu3O7-δ Thin Films

1992 ◽  
Vol 279 ◽  
Author(s):  
E. L. Venturing ◽  
M. P. Siegal ◽  
A. E. White ◽  
S. Y. Hou ◽  
Julia M. Phillips
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Epitaxial Films ◽  
Vortex Pinning ◽  
Ex Situ ◽  
Relaxation Data ◽  
Magnetization Relaxation ◽  
Pinning Potential

ABSTRACTThe appropriate fluence of 2.0 MeV H1 ions has been shown previously to enhance the critical current density Jc by a factor of two at a magnetic field of 0.9 tesla in 1000 Å thick epitaxial films of YBa2Cu3O7-δ grown by the ex situ BaF2 process. The as-grown films exhibit single crystal-like behavior in both atomic ordering and Jc versus temperature and magnetic field. TRIM simulations suggest that H+ irradiation generates mainly point delects throughout the crystal structure. We show here that such defects result in an even greater enhancement of Jc for fields above 1 tesla plus a significant increase in the apparent vortex pinning potential deduced from magnetization relaxation data.

Critical Current Density and Flux Pinning Properties in Superconducting MgB2 with and without SiC Doping

2013 ◽  
Vol 750 ◽  
pp. 293-297
Author(s):  
Wen Xu Sun ◽  
Bao Rong Ni ◽  
Akiyoshi Matsumoto ◽  
Hiroaki Kumakura
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
High Magnetic Field ◽  
Current Density ◽  
Flux Pinning ◽  
Critical Magnetic Field ◽  
Pinning Mechanism ◽  
Pinning Potential ◽  
Force Displacement

It is well known that SiC doping in superconducting MgB2 improves the upper critical magnetic field (Bc2) and the critical current density (Jc) under high magnetic field. However, the relationship between SiC doping and the flux pinning mechanism has not been clarified. In this study, several MgB2 samples with and without SiC doping were prepared by the conventional in situ powder-in-tube method. The critical current densities and the force-displacement characteristics of fluxoids in samples were investigated by an ac inductive measurement (Campbell’s method). The Labusch parameter (αL) and the interaction distance (di) were estimated from the obtained force-displacement profile. It was found that SiC doping enhances the values of αL, but does not change the characteristics of the magnetic field dependence of αL apparently. Namely, αL vs. B3/2 characteristics in the pure samples and SiC doped samples are almost the same. Such a result of αL properties implies that the pinning mechanism in the SiC doped samples could be consistent with the conventional pinning theory. On the other hand, di, which is considered to be proportional to the size of pinning potential, decreases rapidly with increasing magnetic field, especially in the pure samples. For high magnetic field region, the variations of di were deduced to be caused by flux creep. The depth of pinning potential, U0, was estimated by using the values of αL and di. The values of U0 give evidence of that SiC doping can prevent the flux bundles moving to another pinning center under high magnetic field.

STUDY OF THE TEXTURING IN BSCCO-AG TAPES THROUGH MAGNETIC MEASUREMENTS

2000 ◽  
Vol 14 (25n27) ◽  
pp. 3159-3164
Author(s):  
C. FERDEGHINI ◽  
M. R. CIMBERLE ◽  
G. GRASSO ◽  
P. GUASCONI ◽  
A. MALAGOLI ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Magnetic Measurements ◽  
Texture Evolution ◽  
Rolling Direction ◽  
Longitudinal Direction ◽  
Magnetic Method ◽  
Superconducting Compounds

We have developed a method that allows, by a simple set of magnetic measurements, to study the texturing of the grains inside a BSCCO-Ag tape. Because the texture is anisotropic we define the angle ϑ L that identifies the mean grain misalignment angle with respect to the tape surface in longitudinal direction (i.e. rolling direction) and the angle ϑ T in transverse direction. The technique is based on the assumption that, because of the very high anisotropy of the critical current density in BSCCO superconducting compounds, the magnetic moment is essentially generated by the current circulating in the a-b planes of the BSCCO grains. The different magnetisation cycles, measured when the orientation of the magnetic field with respect to the tape surface is changed, depend only on the grain orientation inside the tape, which determines the effective magnetic field component normal to the a-b planes of the grains. Here we present the texture evolution of the BSCCO grains inside silver sheated multifilamentary tape starting from the initial steps of the mechanical deformation up to the final heating stage. The results obtained from the magnetic method are compared with those obtained with other methods, i.e. X-ray diffraction and critical current density anisotropy. Also results obtained on samples prepared in different way will be presented.

The Critical Current Density and the Curvature of the Magnetic Field in Epitaxial YBaCuO Films

1992 ◽  
Vol 170 (2) ◽  
pp. 549-562 ◽  
Author(s):  
D. Glatzer ◽  
A. Forkl ◽  
H. Theuss ◽  
H. U. Habermeier ◽  
H. Kronmüller
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
The Magnetic Field

Anisotropic critical current density and flux pinning mechanism of Fe1+yTe0.6Se0.4 single crystals

2021 ◽  
Author(s):  
Yongqiang Pan ◽  
Nan Zhou ◽  
Bencheng Lin ◽  
Jinhua Wang ◽  
Zengwei Zhu ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Pinning Force ◽  
Magnetization Relaxation ◽  
Pinning Mechanism

Abstract Fe1+yTe0.6Se0.4 has considerable application potential due to its large critical current density (J c) and high upper critical magnetic field (H c2). However, the uncertainty of the anisotropy of J c and the unclear flux-pinning mechanism have limited the application of this material. In this study, the J c in three directions were obtained from magnetic hysteresis loop measurements. A large anisotropy of J c ab /J c c ~ 10 was observed, and the origin of the anisotropy was discussed in details. Flux pinning force densities (F p) were obtained from J c, and a non-scaling behavior was found in the normalized pinning force f p[F p/F p-max] versus the normalized field h[H/H c2]. The peaks of pinning force shift from a high h to a low h with increasing temperature. Based on the vortex dynamics analysis, the peak shift was found to originate from the magnetization relaxation. The J c and F p at critical states free from the magnetic relaxation were regained. According to the Dew-Hughes model, the dominant pinning type in Fe1+yTe0.6Se0.4 clean single crystals was confirmed to be normal point pinning.

Effect of magnetic field on the resistive transition and critical current density of Y-Ba-Cu-O/Ag rolled tapes

1991 ◽  
Author(s):  
G. Swaminathan ◽  
S. Rajendra Kumar ◽  
N. Ramadas ◽  
K. Venugopal ◽  
K. A. Durga Prasad ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Resistive Transition

scholarly journals Enhancement of critical current density in a superconducting NbSe2 step junction

Nanoscale ◽  
2020 ◽  
Vol 12 (22) ◽  
pp. 12076-12082
Author(s):  
Xin He ◽  
Yan Wen ◽  
Chenhui Zhang ◽  
Zhiping Lai ◽  
Eugene M. Chudnovsky ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Transport Properties ◽  
Critical Current ◽  
Current Density ◽  
Vortex Pinning ◽  
Step Junction

We investigate the transport properties of a NbSe2 step junction and verify that the enhancement of the critical current density is due to the vortex pinning at the step junction.

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