Top-seeding melt texture growth of single-domain superconducting pellets

The top-seeding melt texture growth (TSMTG) process is investigated in a small-vertical-thermal-gradient furnace in order to better understand the conditions for growing large single-grain pellets. An crystal was used as seed in a Y123 - Y211 composite with additions. It was shown that the role of the seed is to initiate the sympathetic nucleation growth mechanism. Indeed, the additional driving force induced by the seed is clearly demonstrated by a decrease in the undercooling of the system. The seeding crystal introduces a heterogeneous nucleation centre, leading to a very well controlled nucleation rate. Furthermore, we discuss the relation between intrinsic anisotropic growth rate and the processing rate, showing the importance of the thermal conditions of the texturing process to stabilize a sympathetic growth. By careful control of the texturing parameters, we succeeded in producing single-grain pellets as confirmed by a pole figure experiment and neutron diffraction measurements. The levitation force for pellets of 2 cm in diameter reaches 16 N when an NdFeB magnet of the same diameter is used.

[1]  G. Desgardin,et al.  Influence of , or additions on the microstructure and the critical current density of melt processed YBCO samples , 1996 .

[2]  P. McGinn,et al.  Effects of processing parameters on the levitation force of melt-processed YBa 2 Cu 3 O x , 1995 .

[3]  J. Hull,et al.  GROWTH OF LARGE-DOMAIN YBA2CU3OX WITH NEW SEEDING CRYSTALS OF CANDALO4 AND SRLAGAO4 , 1995 .

[4]  H. Freyhardt,et al.  Growth model for melt-textured Y1Ba2Cu3O7−gd , 1995 .

[5]  Y. Sun,et al.  Growth and possible size limitation of quality single-grain YBa2Cu3O7 , 1994 .

[6]  G. Hong,et al.  Y2BaCuO5 morphology in melt-textured Y-Ba-Cu-O oxides with PtO2.H2O/CeO2 additions , 1994 .

[7]  P. Koidl,et al.  Doping of polycrystalline diamond by boron ion implantation , 1994 .

[8]  C. Varanasi,et al.  Critical current density and microstructure of melt-processed YBa2Cu3Ox with PtO2 additions , 1994 .

[9]  K. No,et al.  Effects of Pt Doping on Microstructure of YBa2Cu3Ox Superconductor Prepared by Directional Solidification , 1994 .

[10]  C. J. Kim,et al.  Epitaxial growth of sol-gel PLZT thin films , 1994 .

[11]  C. Varanasi,et al.  A comparison of the effects of PtO2 and BaSnO3 additions on the refinement of Y2BaCuO5 and magnetization of textured YBa2Cu3O6+x , 1994 .

[12]  Y. Shiohara,et al.  Diffusion solidification model on Y-system superconductors , 1992 .

[13]  M. Harmer,et al.  Mechanism for the Peritectic Reaction and Growth of Aligned Grains in YBa2Cu3O6+x , 1992 .

[14]  R. Brendel,et al.  An infrared dielectric function model for amorphous solids , 1992 .

[15]  M. Murakami,et al.  Flux pinning due to nonsuperconducting particles in melt processed YBaCuO superconductors , 1991 .

[16]  M. Murakami,et al.  Magnetic properties of superconducting permanent magnets of YBa2Cu3Ox , 1991 .

[17]  K. Funaki,et al.  Effect of Y2BaCuO5 Particles on Pinning Characteristics of Y-Ba-Cu-O Prepared by Melt Powder Melt Growth Method , 1991 .

[18]  T. Tiefel,et al.  Microstructure and properties of the Y-Ba-Cu-O superconductor with submicron 211 dispersions , 1991 .

[19]  S. Tanaka,et al.  Preparation of a high-Jc YBCO bulk superconductor by the platinum doped melt growth method , 1991 .

[20]  M. Morita,et al.  Quench and Melt Growth (QMG) Process for Large Bulk Superconductor Fabrication , 1991 .

[21]  M. Murakami,et al.  Magnetization study of YBaCuO prepared by quench and melt growth process , 1990 .

[22]  F. Moon,et al.  Levitation Forces, Relaxation and Magnetic Stiffness of Melt-Quenched YBa2Cu3Ox , 1990 .

[23]  Chu,et al.  Superconductivity at 93 K in a new mixed-phase Yb-Ba-Cu-O compound system at ambient pressure. , 1987, Physical review letters.