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Current percolation and anisotropy in polycrystalline MgB(2).
M Eisterer1, M Zehetmayer, H W Weber
1Atominstitut der Osterreichischen Universitäten, A-1020 Vienna, Austria. eisterer@ati.ac.at
Physical Review Letters
|July 15, 2003
Summary
Anisotropy significantly impacts transport currents in magnesium diboride (MgB2) bulk samples and wires. A new model accurately predicts critical current density using anisotropic London theory, grain boundary pinning, and percolation theory.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Superconductivity
Background:
- Magnesium diboride (MgB2) is a widely studied superconductor with potential applications.
- Understanding factors influencing its critical current density is crucial for device development.
- Anisotropy in MgB2 properties can affect its superconducting performance.
Purpose of the Study:
- To investigate the influence of anisotropy on the transport current in MgB2.
- To develop and validate a model for predicting critical current density in MgB2.
- To correlate model parameters with experimental and theoretical predictions.
Main Methods:
- Development of a critical current density model.
- Incorporation of anisotropic London theory.
- Inclusion of grain boundary pinning and percolation theory.
Main Results:
- The proposed model convincingly reproduces experimental transport current data.
- Calculated critical current densities align well with experimental observations.
- Anisotropy parameters derived from the model show good agreement with existing data.
Conclusions:
- Anisotropy is a key factor governing transport currents in MgB2.
- The developed model provides a reliable framework for predicting MgB2 critical current density.
- The study validates the interplay of anisotropic London theory, grain boundary pinning, and percolation theory in MgB2.