NIST High Temp. Superconducting Materials (HTS) Database

NIST High Temp. Superconducting Materials (HTS) Database:

NIST Standard Reference Database 62

Last Update to Data Content: 1996

DOI: https://doi.org/10.18434/T4KP8J

Bibliographic Information

Title: Formation of a New Superconducting Tetragonal Phase, YBCO-T* (T_c = 87 K) in YBa₂Cu₃O_7-δ
Author(s): S. Subramanian, C.S. Swamy, and H.G. Karge
Publication: Journal of Materials Science Letters Volume: 12 Issue: 12 Year: 1993 Page(s): 928-931
Editor(s): Not Available
Publisher: Chapman and Hall
Language: English
Notes: Not Available
Keywords: Material Specification, Crystallography, Critical Temperature, Magnetic Susceptibility

Materials and Properties

Y:123; [Y-Ba-Cu-O]

Material Specification for Y:123; [Y-Ba-Cu-O] Process: Solid State Reaction
Notes: "The YBCO7 sample was prepared from high-purity (99.99%) Y₂O₃, BaCO₃ and CuO weighed in a 1:2:3 stoichiometric ratio and was mixed well in an agate mortar using acetone. The mixture was calcined at 935 °C for about 48 h with intermittent grindings. The resultant black powder was pressed into pellets and sintered at 935 °C for about 12 h and later annealed under a flow of pure oxygen at 500 °C for about 6 h and cooled to room temperature... a YBCO7 sample was heated to 800 °C under vacuum at 2 °C min^-1 and kept at that temperature for 2 h to remove all desorbed gases, then cooled to room temperature. This was heated in pure oxygen to 500 °C at 2 °C/min and cooled slowly."
Formula: YBa₂Cu₃O_7-x
Informal Name: Y:123
Chemical Family: Y-Ba-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:

Crystallography for Y:123; [Y-Ba-Cu-O]

Crystal System:	Tetragonal
Formula Units per Cell:
Space Group:

**Cell Parameters**
Temp K	a Å	b Å	c Å
296	3.853	--	11.634

Measurement Method: X-ray diffraction
"The X-ray pattern (Siemens X-ray diffractometer using CuK ) (of the initial YBCO7 pellet) indicated the formation of 123 phase without any impurities... The X-ray pattern (of the treated sample) is markedly different... Formation of this new tetragonal phase (we denote it as YBCO-T*)... was confirmed by repeated experiments... we calculated the lattice parameters by the least-square refinement method..."

Cautions: Evaluated Data

Critical Temperature for Y:123; [Y-Ba-Cu-O]

Critical Temperature (K)
87

Measurement Method: SQUID magnetometer
"The analysis of the new YBCO-T* phase by magnetic susceptibility measurements using a superconducting quantum interference device (SQUID) apparatus (Quantum Design, MPMS, (USA) at 10^-4 applied magnetic field showed that this phase was superconducting... having about 80% superconducting volume fraction." No additional measurement details were noted.

Cautions: Evaluated Data

Magnetic Susceptibility for Y:123; [Y-Ba-Cu-O]

Temperature (K)	Magnetic Susceptibility (arbitrary)
6	-8.5
30	-7.5
48	-6.1
66	-4.1
78	-2.3
88	0
100	0