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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: The Structural and Superconducting Properties of the YBa2Cu3O7-δ-HfO2 System
Author(s): J. Koshy, J.K. Thomas, J. Kurian, Y.P. Yadava, and A. D. Damodaran
Publication: Journal of Applied Physics Volume: 73 Issue: 7 Year: 1993 Page(s): 3402-3406
Editor(s): Not Available
Publisher: American Institute of Physics
Language: English
Notes: Not Available
Keywords: Material Specification, Critical Temperature, Resistivity (normal state)

Materials and Properties

Y:123; [Y-Ba-Cu-O]
Material Specification for Y:123; [Y-Ba-Cu-O] Process: Solid State Reaction
Notes: "The YBCO samples were prepared by mixing a stoichiometric amount of high purity (99.9%) Y2O3, BaCO3, and CuO, followed by calcination at 930 °C for 30 h with two intermediate grindings. HfO2 (99.9% pure) powder was added in the range of 0.0 to 5.0 wt% with the calcined YBCO powder and mixed thoroughly. Samples, pressed in the form of pellets (65% green density) having 11 mm diameter and 1.5 mm thickness, were kept in an alumina crucible and sintered at 950 °C for 12 h in air. An automated temperature controlled furnace with the temperature accuracy of ±2 °C was used for the heat treatment. The samples were then subjected to... different cooling treatments: (a) cooled slowly at a rate of 2 °C/min in air or oxygen; (b) quenched in air or in flowing oxygen..."
Formula: YBa2Cu3O7-x•yHfO2
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:

Critical Temperature for Y:123; [Y-Ba-Cu-O]
Mass Fraction of HfO2 (%) Critical Temperature (K)
0 92
1 92
3 92
5 92
Measurement Method: Four-probe method
"The resistivity temperature measurements... were carried out by the four probe method using a Keithley model 181 nanovoltmeter and a Keithley model 221 current source after removing a substantial part of the surface layer of the specimens by polishing. Silver paste was used for point contacts and the temperature was measured by a calibrated copper-constantan thermocouple with an accuracy of ±0.2 K."

Cautions: Evaluated Data
The author indicated that Tc was evaluated as the zero resistance temperature. "Transition temperature of 92 K was obtained for all HfO2-added samples although the room temperature resistivity of the HfO2-added YBCO samples was higher..."
Resistivity (normal state) for Y:123; [Y-Ba-Cu-O]
Cooling Method () Amount of HfO2 () Temperature (K) Resistivity (normal state) (mΩ·cm)
slow cool 0.0 92 0.00
slow cool 0.0 95 1.04
slow cool 0.0 100 1.15
slow cool 0.0 140 1.42
slow cool 0.0 180 1.56
slow cool 0.0 300 1.95
slow cool 0.5 92 0.00
slow cool 0.5 95 1.30
slow cool 0.5 100 1.34
slow cool 0.5 140 1.63
slow cool 0.5 180 1.81
slow cool 0.5 300 2.29
slow cool 1.0 92 0.00
slow cool 1.0 95 1.37
slow cool 1.0 100 1.42
slow cool 1.0 140 1.71
slow cool 1.0 180 1.92
slow cool 1.0 300 2.52
slow cool 2.0 92 0.00
slow cool 2.0 95 1.52
slow cool 2.0 100 1.56
slow cool 2.0 140 1.81
slow cool 2.0 180 2.05
slow cool 2.0 300 2.71
slow cool 3.0 92 0.00
slow cool 3.0 95 1.64
slow cool 3.0 100 1.75
slow cool 3.0 140 2.08
slow cool 3.0 180 2.32
slow cool 3.0 300 2.95
slow cool 5.0 92 0.00
slow cool 5.0 95 1.86
slow cool 5.0 100 2.03
slow cool 5.0 140 2.47
slow cool 5.0 180 2.70
slow cool 5.0 300 3.27
quenched 0.0 97 35.0
quenched 0.0 100 33.7
quenched 0.0 140 30.3
quenched 0.0 300 20.6
quenched 0.5 92 0.00
quenched 0.5 97 1.26
quenched 0.5 100 1.32
quenched 0.5 140 1.68
quenched 0.5 300 2.17
quenched 1.0 92 0.00
quenched 1.0 97 1.48
quenched 1.0 100 1.54
quenched 1.0 140 1.87
quenched 1.0 300 2.53
quenched 2.0 92 0.00
quenched 2.0 97 1.70
quenched 2.0 100 1.82
quenched 2.0 140 2.23
quenched 2.0 300 2.69
quenched 3.0 92 0.00
quenched 3.0 97 1.98
quenched 3.0 100 2.07
quenched 3.0 140 2.51
quenched 3.0 300 3.35
quenched 5.0 92 0.00
quenched 5.0 97 2.07
quenched 5.0 100 2.20
quenched 5.0 140 2.72
quenched 5.0 300 3.60
Measurement Method: Four-probe method
"The resistivity temperature measurements... were carried out by the four probe method using a Keithley model 181 nanovoltmeter and a Keithley model 221 current source after removing a substantial part of the surface layer of the specimens by polishing. Silver paste was used for point contacts and the temperature was measured by a calibrated copper-constantan thermocouple with an accuracy of ±0.2 K."

Cautions: Evaluated Data
Digitized data were obtained from Figures 4 and 5 of the paper.