14 Result(s)
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Chapter and Conference Paper
Transport Properties of Magnetic Metals Near Phase Transitions
The transport properties of magnetic materials near phase transitions have been the subject of rather intense research, both experimental and theoretical, even though spectacular effects are not often observed...
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Article
Simulated growth and microstructure of DyBa2Cu3O7−x with and without Dy2BaCuO5 addition
We present optical observations of magnetically melt-textured DyBa2Cu3O7−x with and without 20 wt. % excess of Dy2BaCuO5. From these observations, we propose some kinetic mechanism of the growth of 123 compounds....
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Article
Magnetic alignment in 2212 Bi-based superconducting system: II. Bi2Sr2Ca1−xDyxCu2O8−yx = 0.2 glass recrystallized in 0.6 T magnetic field
Starting from a glassy precursor, Bi2Sr2Ca1−xDyxCu2O8−y (for x = 0.2) was recrystallized under a 0.6 T magnetic field. After splat quenching, the samples were heated and sintered at different temperatures T1, the...
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Article
Magnetic alignment in 2212 Bi-based superconducting system: Part I. Magnetic orientation of Bi2Sr2Ca1−x(RE)xCu2O8−y [(RE) = Gd, Dy, Ho, Er] powder dispersed in epoxy resin at room temperature
The magnetic anisotropy of rare-earth substituted 2212 materials (Bi2Sr2Ca0.8RE0.2Cu2Ox with RE = Gd, Dy, Ho, Er) is put into evidence. Superconducting powder dispersed in epoxy resin is oriented under an externa...
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Article
Polarized light microstructure analysis of melt-textured DyBa2Cu3O7−x ceramics
We report the microstructure of magnetically melt-textured Dy-123 samples, as observed by polarized light metallography. The phase dimensions, morphology, orientation, nature, and distribution are outlined. Gr...
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Article
Phase Transitions, Patterns and Statistical Mechanics of Front Propagation in a Dynamic Random Impurity Model for Strip, Unusual Trees and Other Geometries
A dynamic random impurity model is studied lor describing the evolution of an advancing interface through a multiphase random medium containing mobile impurities. A short range repulsion between the front and ...
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Article
Directional solidification by appropriate chemically active single crystal seed: An alternative way of generating large superconducting 123 single domain
A Dy2O3 single crystal has been used as a seed for the growth of isothermally melt-textured Dy-123 material. The nucleation-controlled step has been observed to be related to the heterogeneous nucleation of 211 p...
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Article
Studies of Crack Pattern in Two Dimensional Media as Resulting From Ion Beam like or Freezing Destruction
We have numerically studied various models for crack formation in the slow dynamical regime. Two different aspects are presented herein: (i) sputtering with reconstruction and (ii) internal destruction of a po...
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Article
Non Trivial Processes for Obtaining Bi-Based High Tc Superconductors
Dysprosium doped Bi-based 2212 ceramics were synthesized by a melt-texturing growth process in a 1.2T magnetic field, applied perpendicularly to the main axis of a cylindrically shaped sample. The materials we...
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Chapter and Conference Paper
Vortex Pinning and Dynamics in Perovskite Oxides: Thermal Magneto-Transport in the Mixed State
Vortex arrays have been predicted to exist in type-II superconductors by Abrikosov[1]. They are of interest, not only because of technological reasons, i.e. the possibility of blocking the critical current-decay ...
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Article
Two Peak Effect in GMR: A Chemical Effect?
We show that the synthesis conditions have a dramatic influence on the resistivity behavior of calcium and sodium doped LaMnO3. Several samples prepared by lowtemperature techniques exhibit a double-peaked curve ...
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Article
Phase Transition and Pattern of Self-Organized Microstructures in Presence of Mobile Impurities
A growth model starting from a surface and in presence of mobile nonreactive localized impurities has been studied for the statistical physics of the microstructure and the surface roughness through simulation...
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Article
Low-field magnetoresistance in La0.7Ca0.3MnO3 manganite compounds prepared by the spray drying technique
Calcium-substituted lanthanum manganite compounds were synthesized by the spray drying technique. This method—whose main advantages are versatility, high reproducibility and scalability—yields small grain mate...
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Article
High frequency (daily) data analysis of the Southern Oscillation Index. Tsallis nonextensive statistical mechanics approach
Daily data of the Southern Oscillation Index between 1999 and mid-2006 has been analyzed in order to obtain the shape and tails of the partial distribution functions (PDF) of the variability of the index. A m...
