研究目的
To study the influence of the composition of the source of melt for infiltration and CeO2 addition on Yb contamination, microstructure, transition temperature, and critical current density at 77 K in single grain YBCO bulk superconductors prepared by infiltration growth process.
研究成果
The infiltration growth process successfully produced YBCO bulk superconductors with Yb doping from the substrate, leading to chemical pinning effects. CeO2 addition and melt composition influence Yb diffusion, microstructure (Y211 particle size), transition temperature, and critical current density. Optimal pinning requires fine control of dopant concentration and particle distribution, with implications for enhancing superconducting properties in applications.
研究不足
The Yb contamination from the Yb2O3 substrate is unavoidable in this setup, potentially affecting purity and properties. The resolution limit of EDS (0.1 wt.%) may not detect very low Yb concentrations. The study is limited to specific compositions and conditions; results may not generalize to other dopants or growth methods.
1：Experimental Design and Method Selection:
The infiltration growth method was used to prepare single grain YBCO bulk superconductors. The solid phase precursor was synthesized via solid state reaction from Y2O3 and BaCuO2 powders. Different compositions of the liquid source melt and CeO2 additions were tested to study their effects.
2：Sample Selection and Data Sources:
Three samples (S_1, S_2, S_3) were prepared with variations in liquid source composition and CeO2 addition. Samples were cut from the upper part of single crystals for analysis.
3：List of Experimental Equipment and Materials:
Precursor powders (Y2O3, BaCuO2, CeO2, CuO), grinding mill, uniaxial press, chamber furnace, Al2O3 plate, MgO single crystal, Yb2O3 base, Nd123 seed, optical microscope, scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS), equipment for magnetic measurements at liquid nitrogen temperature.
4：Experimental Procedures and Operational Workflow:
Pellets were mixed, pressed, and synthesized. The growth setup included layers of liquid source pellet, solid phase pellet, and seed on a Yb2O3 base. Heating to 1040°C for infiltration, followed by slow cooling through peritectic temperature for crystal growth. Samples were oxygenated at 410°C for 400 hours. Microstructure was observed with optical microscope and SEM-EDS; superconducting properties were measured magnetically.
5：Data Analysis Methods:
Image analysis software for Y211 particle size distribution, EDS for Yb concentration, extended Bean model for critical current density evaluation from magnetic loops.
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