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采用人工掺杂Y-211相的方法以及熔融织构生长结合顶部籽晶工艺制备了不同211粒子含量的 准单畴熔融织构的YBCO块材料,样品致密度高,体密度大于62g/cm3,机械强 度好,振动样品磁强计测量结果表明,样品在温度30K、磁场06T下,其Jc仍 达到123×106A/cm2.在温度70K、磁场2T条件下,Jc 仍高达135×104A/cm2,而且临界电流密度对磁场不敏感.扫描电 子显微镜分析也表明,Y-211相的人工掺杂,能改善织构样品的生长状况,减小微裂纹,同 时,掺杂的Y-211粒子能作为强的钉扎中心,因此,这种工艺能精确地控制样品中Y-211粒子 的含量,所制备的样品中Y-211粒子分布越均匀,尺寸越小,其钉扎效果越好.从大量实验结 果比较得出,1∶05是最佳的掺杂比例.This paper describes the method of artificial doping Y-211 phase and melt-textur ed growth with a top-seeded technique to prepare the quasi-single crystal domain YBCO bulk materials with various Y-211 particle contents.The specimens obtained have high density (more than 62g/cm3) and good mechanical toughnes s.The Jc of specimens reaches 123×106A/cm2 u nder 06T at 30K and 135×104A/cm2 under 2 T at 70K.The scanning electron microscope observation of specimens indicates that Y-211 part icles can improve the quality of melt-textured YBCO superconductor and reduce th e microcrack of specimens.Combining the microstructures with Jc measu rements shows that the smaller the particle size,the more homogeneous the partic le distribution,the higher the pinning effectiveness.The best ratio of Y-123 to Y-211 for the superconductor specimens is 1∶05 in moles,in which the Y-211 pa rticles are uniformly distributed and their size is about 200nm.
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Keywords:
- quasi-single domain superconductor /
- melt-texture /
- critical current density Jc /
- magnetic flux pinning center







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