scholarly journals Point defect induced giant enhancement of flux pinning in Co-doped FeSe0.5Te0.5 superconducting single crystals

AIP Advances ◽  
2017 ◽  
Vol 7 (11) ◽  
pp. 115016 ◽  
Author(s):  
Lina Sang ◽  
Pankaj Maheswari ◽  
Zhenwei Yu ◽  
Frank F. Yun ◽  
Yibing Zhang ◽  
...  
Keyword(s):  
Point Defect ◽  
Single Crystals ◽  
Flux Pinning ◽  
Co Doped

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.

scholarly journals Investigations on Crystalline Perfection, Raman Spectra and Optical Characteristics of Transition Metal (Ru) Co-Doped Mg:LiNbO3 Single Crystals

ACS Omega ◽  
2021 ◽  
Author(s):  
M. K. Raseel Rahman ◽  
B. Riscob ◽  
Rajeev Bhatt ◽  
Indranil Bhaumik ◽  
Sarveswaran Ganesamoorthy ◽  
...  
Keyword(s):  
Transition Metal ◽  
Single Crystals ◽  
Raman Spectra ◽  
Optical Characteristics ◽  
Crystalline Perfection ◽  
Co Doped

Enhanced flux pinning and fishtail effect in spiral grown Bi2Sr2CaCu2Oy single crystals

1997 ◽  
Vol 282-287 ◽  
pp. 2125-2126 ◽  
Author(s):  
X.L. Wang ◽  
J. Horvat ◽  
H.K. Liu ◽  
S.X. Dou
Keyword(s):  
Single Crystals ◽  
Flux Pinning

Growth and optical properties of Eu2+/Li+-co-doped SrB4O7 single crystals

2011 ◽  
Vol 72 (4) ◽  
pp. 252-255 ◽  
Author(s):  
Zhiwei Jiao ◽  
Shaoxia Li ◽  
Qingfeng Yan ◽  
Xiaoqing Wang ◽  
Dezhong Shen
Keyword(s):  
Optical Properties ◽  
Single Crystals ◽  
Co Doped

Excited state relaxation dynamics and up-conversion phenomena in Gd 3 (Al,Ga) 5 O 12 single crystals co-doped with holmium and ytterbium

2016 ◽  
Vol 656 ◽  
pp. 573-580 ◽  
Author(s):  
W. Ryba-Romanowski ◽  
J. Komar ◽  
T. Niedźwiedzki ◽  
M. Głowacki ◽  
M. Berkowski
Keyword(s):  
Excited State ◽  
Single Crystals ◽  
Relaxation Dynamics ◽  
Co Doped

Magnetic properties of undoped and Co-doped n-type β–FeSi2.5 single crystals

2002 ◽  
Vol 17 (11) ◽  
pp. 2960-2965 ◽  
Author(s):  
E. Arushanov ◽  
L. Ivanenko ◽  
D. Eckert ◽  
G. Behr ◽  
U. K. Rößler ◽  
...  
Keyword(s):  
Activation Energy ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
External Field ◽  
Single Crystals ◽  
Spin Glasses ◽  
Paramagnetic Centers ◽  
Temperature Dependent ◽  
Paramagnetic Curie Temperature ◽  
Co Doped

Results of magnetization and magnetic susceptibility measurements on undoped and Co-doped FeSi2.5 single crystals are presented. The temperature dependence of the magnetic susceptibility of the Co-doped sample in the range of 5–300 K can be explained by temperature-dependent contributions due to paramagnetic centers and the carriers excited thermally in the extrinsic conductivity region. The values of the paramagnetic Curie temperature and activation energy of the donor levels were estimated. It is also shown that the magnetic susceptibility of Co-doped samples cooled in zero external field and in a field are different. This resembles the properties of spin-glasses and indicates the presence of coupling between magnetic centers.

Low‐field flux pinning in twinned and detwinned single crystals of YBa2Cu3O7−x

1991 ◽  
Vol 58 (14) ◽  
pp. 1566-1568 ◽  
Author(s):  
L. J. Swartzendruber ◽  
D. L. Kaiser ◽  
F. W. Gayle ◽  
L. H. Bennett ◽  
A. Roytburd
Keyword(s):  
Single Crystals ◽  
Flux Pinning ◽  
Low Field

Flux Pinning in Y1Ba2Cu3O7-∂ Single Crystals

1988 ◽  
pp. 267-271 ◽  
Author(s):  
L. Fruchter ◽  
C. Giovannella ◽  
G. Collin ◽  
I. A. Campbell
Keyword(s):  
Single Crystals ◽  
Flux Pinning

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.

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