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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: An Ultrasonic Study of Superconducting and Non-Superconducting GdBa2Cu3O7-x
Author(s): D.P. Almond, Qingxian Wang, J. Freestone, E.P. Lambson, B. Chapman, and G.A. Saunders
Publication: Journal of Physics: Condensed Matter Volume: 1 Issue: Not Available Year: 1989 Page(s): 6853-6864
Editor(s): Not Available
Publisher: IOP Publishing Ltd
Language: English
Notes: Not Available
Keywords: Material Specification, Density (mass), Crystallography, Magnetic Susceptibility, Thermal Expansion, Debye Temperature, Shear Modulus, Bulk Modulus, Sound Velocity

Materials and Properties

Gd:123; [Gd-Ba-Cu-O]
Material Specification for Gd:123; [Gd-Ba-Cu-O] Process: Solid State Reaction
Notes: "The... material studied was prepared by reacting appropriate proportions of Gd2O3, BaO and CuO at 940 °C for 48 h in air. The product was ground into a fine powder, pressed into cylindrical pellets (about 7 mm in diameter, and 9 mm long), sintered at 940 °C in an oxygen flow for 48 h and then cooled slowly to room temperature. The end faces of the sample used for ultrasonic measurements were polished flat and parallel to about 10-4 rad... Microstructural examination revealed the material to be uniformly porous with pore sizes in the range 5-15 µm and to have a grain size of predominantly less than 5 µm."
Formula: GdBa2Cu3O7-x
Informal Name: Gd:123
Chemical Family: Gd-Ba-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:

Density (mass) for Gd:123; [Gd-Ba-Cu-O]
Theoretical Density (g/cm3) Density (g cm-3)
7.138 5.549
Measurement Method: Unknown density method
No measurement details were noted.

Cautions: Unevaluated Data
Crystallography for Gd:123; [Gd-Ba-Cu-O] div class="table-responsive">
Crystal System: Orthorhombic
Formula Units per Cell:
Space Group:
Cell Parameters
Temp K a Å b Å c Å
117 3.916 3.855 11.722
153 3.918 3.856 11.727
173 3.920 3.856 11.730
192 3.920 3.858 11.734
250 3.922 3.861 11.744
269 3.924 3.862 11.752
290 3.925 3.862 11.753
Measurement Method: X-ray diffraction

Cautions: Unevaluated Data
No measurement details were noted. Digitized data were obtained from Figure 3 of the paper.
Magnetic Susceptibility for Gd:123; [Gd-Ba-Cu-O]
Temperature (K) Magnetic Susceptibility (arbitrary)
90 -2.3
97 -1.5
97 -0.6
99 0.0
175 0.0
Measurement Method: Ac susceptibility

Cautions: Unevaluated Data
No measurement details were noted. Digitized data were obtained from Figure 2 of the paper.
Thermal Expansion for Gd:123; [Gd-Ba-Cu-O]
Direction () Thermal Expansion (10-6 K-1)
a-axis 12.2±0.3
b-axis 11.2±0.3
c-axis 16.4±0.3
Measurement Method: X-ray diffraction

Cautions: Unevaluated Data
No measurement details were noted.
Debye Temperature for Gd:123; [Gd-Ba-Cu-O]
Temperature (K) Debye Temperature (K)
4.2 426 ± 15
Measurement Method: Ultrasonic pulse echo
"Conventional ultrasonic pulse echo techniques were employed to make measurements of sound velocity and attenuation in the sample. Quartz transducers, bonded to a sample end face using Nonaq stop-cock grease, were used to generate and detect the ultrasonic waves. Sound velocity measurements were made by the pulse echo overlap method... to an accuracy of better than 1 part in 104. The standard transducer correction... was incorporated in the analysis. Changes in ultrasonic attenuation were monitored by the pulse comparison technique... to an accuracy of 0.1 dB in echo amplitude. At all times at least five well resolved ultrasonic pulse echoes were available for measurement, ensuring that true changes in sample attenuation were being recorded. The sample was cooled to liquid helium temperature in a vacuum cryostat backfilled with a reduced atmosphere of dry nitrogen or helium exchange gas. The sample temperature was monitored with an accuracy of better than one degree using a gold-iron thermcouple bonded to the sample, and cooling and warming rates of less than one degree per minute were used throughout."

Cautions: Evaluated Data
Shear Modulus for Gd:123; [Gd-Ba-Cu-O]
Temperature (K) Shear Modulus (GPa)
4.2 64.5
Measurement Method: Ultrasonic pulse echo
"Conventional ultrasonic pulse echo techniques were employed to make measurements of sound velocity and attenuation in the sample. Quartz transducers, bonded to a sample end face using Nonaq stop-cock grease, were used to generate and detect the ultrasonic waves. Sound velocity measurements were made by the pulse echo overlap method... to an accuracy of better than 1 part in 104. The standard transducer correction... was incorporated in the analysis. Changes in ultrasonic attenuation were monitored by the pulse comparison technique... to an accuracy of 0.1 dB in echo amplitude. At all times at least five well resolved ultrasonic pulse echoes were available for measurement, ensuring that true changes in sample attenuation were being recorded. The sample was cooled to liquid helium temperature in a vacuum cryostat backfilled with a reduced atmosphere of dry nitrogen or helium exchange gas. The sample temperature was monitored with an accuracy of better than one degree using a gold-iron thermcouple bonded to the sample, and cooling and warming rates of less than one degree per minute were used throughout."

Cautions: Evaluated Data
Bulk Modulus for Gd:123; [Gd-Ba-Cu-O]
Temperature (K) Bulk Modulus (GPa)
4.2 84.6
Measurement Method: Ultrasonic pulse echo
"Conventional ultrasonic pulse echo techniques were employed to make measurements of sound velocity and attenuation in the sample. Quartz transducers, bonded to a sample end face using Nonaq stop-cock grease, were used to generate and detect the ultrasonic waves. Sound velocity measurements were made by the pulse echo overlap method... to an accuracy of better than 1 part in 104. The standard transducer correction... was incorporated in the analysis. Changes in ultrasonic attenuation were monitored by the pulse comparison technique... to an accuracy of 0.1 dB in echo amplitude. At all times at least five well resolved ultrasonic pulse echoes were available for measurement, ensuring that true changes in sample attenuation were being recorded. The sample was cooled to liquid helium temperature in a vacuum cryostat backfilled with a reduced atmosphere of dry nitrogen or helium exchange gas. The sample temperature was monitored with an accuracy of better than one degree using a gold-iron thermcouple bonded to the sample, and cooling and warming rates of less than one degree per minute were used throughout."

Cautions: Evaluated Data
Sound Velocity for Gd:123; [Gd-Ba-Cu-O]
Mode () Heating Condition () Temperature (K) Sound Velocity (km/s)
Longitudinal Increasing 9 4.158
Longitudinal Increasing 52 4.138
Longitudinal Increasing 103 4.103
Longitudinal Increasing 154 4.074
Longitudinal Increasing 197 4.050
Longitudinal Increasing 216 4.055
Longitudinal Increasing 231 4.046
Longitudinal Increasing 235 4.001
Longitudinal Increasing 251 3.972
Longitudinal Decreasing 9 4.156
Longitudinal Decreasing 52 4.147
Longitudinal Decreasing 103 4.119
Longitudinal Decreasing 154 4.095
Longitudinal Decreasing 197 4.066
Longitudinal Decreasing 199 4.037
Longitudinal Decreasing 205 4.001
Longitudinal Decreasing 251 3.972
Shear Increasing 11 2.552
Shear Increasing 50 2.542
Shear Increasing 100 2.517
Shear Increasing 153 2.503
Shear Increasing 199 2.482
Shear Increasing 225 2.476
Shear Increasing 235 2.452
Shear Increasing 252 2.443
Shear Decreasing 11 2.552
Shear Decreasing 50 2.542
Shear Decreasing 102 2.528
Shear Decreasing 151 2.509
Shear Decreasing 192 2.491
Shear Decreasing 202 2.462
Shear Decreasing 252 2.443
Measurement Method: Ultrasonic pulse echo
"Conventional ultrasonic pulse echo techniques were employed to make measurements of sound velocity and attenuation in the sample. Quartz transducers, bonded to a sample end face using Nonaq stop-cock grease, were used to generate and detect the ultrasonic waves. Sound velocity measurements were made by the pulse echo overlap method... to an accuracy of better than 1 part in 104. The standard transducer correction... was incorporated in the analysis. Changes in ultrasonic attenuation were monitored by the pulse comparison technique... to an accuracy of 0.1 dB in echo amplitude. At all times at least five well resolved ultrasonic pulse echoes were available for measurement, ensuring that true changes in sample attenuation were being recorded. The sample was cooled to liquid helium temperature in a vacuum cryostat backfilled with a reduced atmosphere of dry nitrogen or helium exchange gas. The sample temperature was monitored with an accuracy of better than one degree using a gold-iron thermcouple bonded to the sample, and cooling and warming rates of less than one degree per minute were used throughout."

Cautions: Evaluated Data
Digitized data were obtained from Figure 1 of the paper.