Browse Prior Art Database

Crystal Growth of YBa2Cu3O7-w in BeO

IP.com Disclosure Number: IPCOM000108181D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Feild, C: AUTHOR [+2]

Abstract

A process is disclosed for the growth of single crystals of YBa2Cu3O7-w (123). The molten phase is contained in dense ceramic BeO crucibles. The crucibles avoid the unusual creep which prevents long term confinement of the extremely reactive flux. The electropositive nature of the Ba ion in the melt makes the flux reactive with most other refractories.

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Crystal

Growth of YBa2Cu3O7-w in BeO

      A process is disclosed for the growth of single crystals of
YBa2Cu3O7-w (123).  The molten phase is contained in dense ceramic
BeO crucibles.  The crucibles avoid the unusual creep which prevents
long term confinement of the extremely reactive flux.  The
electropositive nature of the Ba ion in the melt makes the flux
reactive with most other refractories.

      The crystals grow from a non-stoichiometric melt containing 3%
Y, 27% Ba and 70% Cu.  Appropriate weights of the constituent oxides
are heated in a beryllium oxide crucible to 975~C, soaked for 3.0
hours, cooled at 2~C/hour to 650~C.  The furnace then cools at
100~C/hour to room temperature. 

Crystals

annealed for 12 hours in
oxygen at 420~C possess a superconducting transition of 92~K and a
transition width of 0.5~K.  Beryllium is not found in the resulting
crystals within the limits of detection of an Energy Dispersive Xray
Diffraction Technique.

      With  a container that holds the liquid phase, crystals can be
pulled from the melt without contamination.  The stable liquid phase
also provides an environment for rapid introduction of substrates for
film growth by liquid phase epitaxy.

      Disclosed anonymously.