Irradiation Effect of Slow Neutrons on Mechanical Behaviour Related to Flux Pinning In YBa2Cu3Oy

1991 ◽  
Vol 235 ◽  
Author(s):  
J. S. Zhu ◽  
J. Li ◽  
Y. N. Wang ◽  
J. R. Jin ◽  
M. Gu ◽  
...  
Keyword(s):  
Internal Friction ◽  
Mechanical Behaviour ◽  
Flux Pinning ◽  
Magnetic Hysteresis ◽  
Slow Neutron ◽  
Magnetic Hysteresis Loop ◽  
Irradiation Effect ◽  
Before And After ◽  
Mechanical Dissipation ◽  
Vibrating Reed

ABSTRACTInternal friction and modulus in YBa2Cu3Oy, which are related to flux pinning, were examined by means of the vibrating reed technique before and after the slow neutron irradiation to different fluences. Both the decrease of mechanical dissipation and the increase of the modulus associated with strongly enhanced flux pinning were observed in a sample irradiated up to a suitable fluence. However, a decrease of modulus and magnetic hysteresis loop was found after further irradiation. A change in the microstructure of the irradiated material is used to explain the observed phenomena.

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.

Mechanical Behaviors of Flux Pinning in GdxY1−x-Ba2Cu3Oy

1992 ◽  
Vol 275 ◽  
Author(s):  
J. S. Zhu ◽  
J. Li ◽  
X. M. Lu ◽  
X. Jin ◽  
M. Gu ◽  
...  
Keyword(s):  
Flux Pinning ◽  
Magnetic Hysteresis ◽  
Rare Earth Ions ◽  
Vibrating Sample Magnetometer ◽  
Mechanical Behaviors ◽  
Mechanical Measurement ◽  
High Tc ◽  
High Tc Superconductor ◽  
Vibrating Reed ◽  
Practicable Method

ABSTRACTThe mechanical behaviors of flux pinning in GdxY1−xBa2Cu3Oy with various concentration of Gd were studied comparatively by means of a vibrating reed technique. Both the internal friction and the modulus increased with enhanced flux pinning due to the increasing of Gd content in GdxY1−xBa2Cu3Oy. It was in accordance with the results of the magnetic hysteresis measurements using a vibrating sample magnetometer. These results indicated that the substitution of magnetic rare-earth ions is a practicable method for improving the flux pinning in high Tc superconductor and the mechanical measurement of flux pinning as a judgement for the superconductivity of sample was proved.

The stability of dislocation networks under various oxygen-doping conditions in superconducting Bi2Sr2CaCu2Oy single crystals and their influence on the flux pinning properties

1994 ◽  
Vol 52 ◽  
pp. 802-803
Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier
Keyword(s):  
Single Crystals ◽  
Oxygen Content ◽  
Basal Plane ◽  
Flux Pinning ◽  
Pinning Centers ◽  
Before And After ◽  
Anomalous Peak ◽  
Basal Plane Dislocation ◽  
The Stability ◽  
Further Development

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.

Correlation between Anomalous Peak Effect in Magnetic Hysteresis Loop and Nanoscale Structure forNdBa2Cu3O7-δSingle-Crystal Superconductor

1996 ◽  
Vol 35 (Part 1, No. 7) ◽  
pp. 3882-3886 ◽  
Author(s):  
Masaru Nakamura ◽  
Tsukasa Hirayama ◽  
Yasuji Yamada ◽  
Yuichi Ikuhara ◽  
Yuh Shiohara
Keyword(s):  
Hysteresis Loop ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Peak Effect ◽  
Anomalous Peak ◽  
Nanoscale Structure

Magnetic Hysteresis Loop of Single Co Nano-islands

2008 ◽  
Vol 47 (12) ◽  
pp. 9013-9015 ◽  
Author(s):  
Guillemin Rodary ◽  
Sebastian Wedekind ◽  
Dirk Sander ◽  
Jürgen Kirschner
Keyword(s):  
Hysteresis Loop ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop

scholarly journals Developing a reference material set for the magnetic properties of NdFeB alloy-based hard magnetic materials

2019 ◽  
Vol 15 (1) ◽  
pp. 21-27
Author(s):  
E. A. Volegova ◽  
T. I. Maslova ◽  
V. O. Vas’kovskiy ◽  
A. S. Volegov
Keyword(s):  
Magnetic Properties ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Magnetic Loss ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Hysteresis Loop ◽  
Magnetic Characteristics ◽  
Hard Magnetic Materials ◽  
Certified Values

Introduction The introduction indicates the need for the use of permanent magnets in various technology fields. The necessity of measuring the limit magnetic hysteresis loop for the correct calculation of magnetic system parameters is considered. The main sources of error when measuring boundary hysteresis loops are given. The practical impossibility of verifying blocks of magnetic measuring systems element-by-element is noted. This paper is devoted to the development of reference materials (RMs) for the magnetic properties of hard magnetic materials based on Nd2Fe14B, a highly anisotropic intermetallic compound.Materials and measuring methods Nd-Fe-B permanent magnets were selected as the material for developing the RMs. RM certified values were established using a CYCLE‑3 apparatus included in the GET 198‑2017 State Primary Measurement Standard for units of magnetic loss power, magnetic induction of constant magnetic field in a range from 0.1 to 2.5 T and magnetic flux in a range from 1·10–5 to 3·10–2 Wb.Results and its discussion Based on the experimentally obtained boundary hysteresis loops, the magnetic characteristics were evaluated, the interval of permitted certified values was set, the measurement result uncertainty of certified values was estimated, the RM validity period was established and the first RM batch was released.Conclusion On the basis of conducted studies, the RM type for magnetic properties of NdFeB alloy-based hard magnetic materials was approved (MS NdFeB set). The developed RM set was registered under the numbers GSO 11059–2018 / GSO 11062–2018 in the State RM Register of the Russian Federation.

Ageing behavior study of 5Cr–0.5Mo steel by magnetic Barkhausen emissions and magnetic hysteresis loop techniques

2007 ◽  
Vol 40 (2) ◽  
pp. 173-178 ◽  
Author(s):  
J.N. Mohapatra ◽  
A.K. Panda ◽  
M.K. Gunjan ◽  
N.R. Bandyopadhyay ◽  
A. Mitra ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Behavior Study

Fabrication of Hexagonal Ni Micro/Nano Plates by a Facile Hydrothermal Reduction Route

2014 ◽  
Vol 898 ◽  
pp. 173-176
Author(s):  
Jun Zhang ◽  
Hai Rui Yao ◽  
Hua Bo Li ◽  
Jing Jing Li ◽  
Xiao Kang Bai
Keyword(s):  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Face Centered Cubic ◽  
Hydrothermal Route ◽  
Nickel Metal ◽  
Structure Directing Agent ◽  
X Ray ◽  
Facile Hydrothermal Route ◽  
Face Centered ◽  
Hydrothermal Reduction

Hexagonal Ni micro/nanoplates were successfully prepared via a facile hydrothermal route using the polyvinylpyrrolidone as structure-directing agent. It has been verified from x-ray powder diffraction and transmission electronic microscopy that as-prepared products with high purity and fine dispersity belong to face-centered cubic microstructure of nickel metal. The magnetic hysteresis loop of the hexagonal Ni micro/nanoplates exhibits the ferromagnetic characteristics, and its coercivity increases by 25 % in comparison with the bulk nickel materials. The possible mechanism of the formation of hexagonal micro/nanoplates was suggested.

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