Fabrication of large grain Nd-Ba-Cu-O by self-seeded melt growth

Author

Cardwell, D.A. ; Kambara, M. ; Babu, N. Hari ; Smith, P.J. ; Shi, Y.

Author_Institution

Interdisciplinary Res. Centre in Superconductivity, Cambridge Univ., UK

Volume

11

Issue

1

fYear

2001

fDate

3/1/2001 12:00:00 AM

Firstpage

3712

Lastpage

3715

Abstract

Large, single grain Nd-Ba-Cu-O (NdBCO) samples containing Nd-422 phase inclusions have been fabricated successfully using NdBCO self-seeds by two melt processing techniques under reduced oxygen partial pressure. The first technique involves hot seeding where the seed crystal is placed onto the sample surface at the peritectic temperature. The second method involves doping precursor powder with Au and Ag to reduce the peritectic decomposition temperature of the material. This enables seeding to be achieved by introducing an undoped Nd-123 seed to the sample surface at room temperature, which simplifies processing significantly. This paper compares the microstructure of large grain NdBCO samples fabricated by the two techniques including the dependence of growth rate on undercooling, processing atmosphere and the size and distribution of Nd-422 in the Nd-123 phase matrix

Keywords

barium compounds; crystal growth from melt; decomposition; grain size; high-temperature superconductors; inclusions; melt texturing; neodymium compounds; undercooling; 20 C; Ag; Au; Nd-123 phase matrix; Nd-422 phase inclusions; Nd-Ba-Cu-O; NdBCO; NdBa₂Cu₃O₇:Ag,Au; doping precursor powder; fabrication; growth rate; hot seeding; large grain Nd-Ba-Cu-O; melt processing; microstructure; peritectic decomposition temperature; peritectic temperature; processing atmosphere; reduced oxygen partial pressure; room temperature; self-seeded melt growth; single grain Nd-Ba-Cu-O; undercooling; Atmosphere; Crystalline materials; Fabrication; Gold; High temperature superconductors; Melt processing; Powders; Superconducting materials; Superconductivity; Telephony;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.919870

Filename

919870