Direct Evidence of the Anisotropic Structure of Vortices Interacting    with Columnar Defects in High-Temperature Superconductors    through the Analysis of Lorentz Images

A chemical approach to the formation of columnar defects involving the growth and incorporation of MgO nanorods into high temperature superconductors (HTS's) has been developed. MgO nanorods were incorporated into Bi2Sr2CaCu2Oz, Bi2Sr2Ca2Cu3Oz, and Tl2Ba2Ca2Cu3Oz superconductors at areal densities up to 2 × 1010/cm2. Microstructural analyses of the composites demonstrate that the MgO nanorods create a columnar defect structure in the HTS matrices, form a compositionally sharp interface with the matrix, and self-organize into orientations perpendicular and parallel to the copper oxide planes. Measurements of the critical current density demonstrate significant enhancements in the MgO nanorod/HTS composites at elevated temperatures and magnetic fields compared with reference samples.

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Structure of Magnetic Fields in High Temperature Superconductors with Columnar Defects

Review of Progress in Quantitative Nondestructive Evaluation ◽

10.1007/978-1-4613-0383-1_182 ◽

1996 ◽

pp. 1391-1397

Author(s):

M. Benkraouda ◽

M. Ledvij

Keyword(s):

High Temperature ◽

Magnetic Fields ◽

High Temperature Superconductors ◽

Columnar Defects

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STUDY OF KINETIC FRICTION OF SOLID USING DRIVEN LATTICE OF QUANTIZED VORTEX IN HIGH-TEMPERATURE SUPERCONDUCTORS–A NEW ROUTE TO STUDY SOLID-SOLID FRICTION

International Journal of Modern Physics B ◽

10.1142/s0217979205028827 ◽

2005 ◽

Vol 19 (01n03) ◽

pp. 463-470 ◽

Cited By ~ 2

Author(s):

ATSUTAKA MAEDA ◽

YUKICHI INOUE ◽

HARUHISA KITANO ◽

SATORU OKAYASU ◽

ICHIRO TSUKADA

Keyword(s):

Magnetic Field ◽

High Temperature ◽

Cuprate Superconductors ◽

High Temperature Superconductors ◽

Magnetic Vortex ◽

Kinetic Friction ◽

Columnar Defects ◽

Solid Friction ◽

Ac Current ◽

Microwave Techniques

We show that quantized magnetic vortex lattice in high-temperature cuprate superconductors driven by dc or ac current is a very good model system for investigating physics of friction of solid. Based on the dc I-V characteristic measurement and viscosity measurement using microwave techniques in Bi 2 Sr 2 CaCu 2 O y and La 1.85 Sr 0.15 CuO 4, the corresponding kinetic friction was obtained as functions of temperature, magnetic field and driving current density. With increasing magnetic field and temperature, velocity dependence of kinetic friction behaves as that at interfaces with weak interaction of solid. This result means that we can control the kinetic friction, and that systematic experiments are available in a reproducible manner with using this system. Behavior of the kinetic friction at higher velocities (~1 km/s) agrees well with a two-class potential model at finite temperatures. Irradiation of the columnar defects was found to move the system closer to the so-called Amontons-Coulomb friction. This suggests that the random potential created by the strong pinning centers plays an important role of the validity of Amontons-Coulomb law.

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