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: Uniaxial Pressure Dependence of T_c of Untwinned YBa₂Cu₃O_x Single Crystals for x=6.5-7
Author(s): O. Kraut, C. Meingast, G. Brauchle, H. Claus, A. Erb, G. Muller-Vogt, and H. Wuhl
Publication: Physica C Volume: 205 Issue: Not Available Year: 1993 Page(s): 139-146
Editor(s): Not Available
Publisher: Elsevier Science Publishers B.V.
Language: English
Notes: Not Available
Keywords: Material Specification, Critical Temperature, Thermal Expansion

Materials and Properties

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

Material Specification for Y:123; [Y-Ba-Cu-O] Process: Crystal Growth
Notes: The authors cite H. Claus et al., Physica C, Vol. 198, 41 (1992), and summarize the procedure as follows. "... single crystals were grown in Y₂O₃-stabilized ZrO₂ crucibles... The O-content was varied by annealing the crystals between 400-520 °C at (0.1 MPa = 1 atm) O₂ for x=6.85-6.95, and at 520 °C and varying oxygen pressure for x < 6.85, respectively... Both twinned and untwinned crystals were examined. Relatively thick (about 0.5 mm along the c-axis) twinned crystals were used for the dilatometric measurements along the c-axis, since the detwinned crystals (typical thickness 0.1-0.2 mm) proved too thin for reliable c-axis measurements... Untwinned crystals... were required to resolve the anisotropy within the a,b plane. Detwinning was accomplished by applying a uniaxial stress (about 0.1 GPa) at 400-520 °C."
Formula: YBa₂Cu₃O_x
Informal Name: Y:123
Chemical Family: Y-Ba-Cu-O
Chemical Class: Oxide
Structure Type: Single Crystal
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:

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

Crystal Condition ()	x of O_x (formula units)	Critical Temperature (K)
Twinned	6.94	89.5 ± 1.0
Twinned	6.93	89.7 ± 0.4
Twinned	6.91	90.1 ± 0.3
Twinned	6.81	87.3 ± 1.6
Twinned	6.70	71.2 ± 1.4
Twinned	6.61	58.7 ± 0.6
Twinned	6.89	90.8 ± 0.3
Twinned	6.82	87.7 ± 0.7
Twinned	6.63	61.1 ± 1.0
Untwinned	6.93	89.7 ± 0.4
Untwinned	6.73	76.3 ± 3.0
Untwinned	6.59	59.9 ± 0.8
Untwinned	6.54	55.5 ± 0.6

Measurement Method: SQUID magnetometer
"T_c values (were) determined with a DC SQUID magnetometer..." No additional measurement details were noted.

Cautions: Evaluated Data

Thermal Expansion for Y:123; [Y-Ba-Cu-O]

x of O_x (formula units)	Axis ()	Temperature (K)	Thermal Expansion (10^-6 K^-1)
6.93	a-axis	8	0.0
6.93	a-axis	43	1.7
6.93	a-axis	65	3.3
6.93	a-axis	73	3.7
6.93	a-axis	90	3.7
6.93	a-axis	91	5.3
6.93	a-axis	126	7.4
6.93	a-axis	147	8.2
6.93	a-axis	198	9.3
6.93	b-axis	21	0.0
6.93	b-axis	58	0.1
6.93	b-axis	80	1.5
6.93	b-axis	89	2.5
6.93	b-axis	93	1.3
6.93	b-axis	131	2.6
6.93	b-axis	161	4.0
6.93	b-axis	200	5.9
6.93	c-axis	21	0.0
6.93	c-axis	49	4.9
6.93	c-axis	90	11.1
6.93	c-axis	134	14.4
6.93	c-axis	143	14.6
6.93	c-axis	173	16.2
6.93	c-axis	198	16.5
6.59	a-axis	13	0.2
6.59	a-axis	48	1.7
6.59	a-axis	74	3.5
6.59	a-axis	113	5.0
6.59	a-axis	148	6.5
6.59	b-axis	199	7.6
6.59	b-axis	12	0.0
6.59	b-axis	38	0.3
6.59	b-axis	55	0.9
6.59	b-axis	76	1.0
6.59	b-axis	116	3.1
6.59	b-axis	168	5.3
6.59	b-axis	199	7.0
6.61	c-axis	9	0.2
6.61	c-axis	23	1.7
6.61	c-axis	47	5.7
6.61	c-axis	85	9.6
6.61	c-axis	125	12.6
6.61	c-axis	142	13.1
6.61	c-axis	151	13.1
6.61	c-axis	173	14.4
6.61	c-axis	199	15.4

Measurement Method: Capacitance dilatometer
The authors cite C. Meingast et al., Phys. Rev. B, Vol. 41, 11299 (1990), and summarize the procedure as follows. "The expansivity α(T)=dln L/dT was measured with an ultrahigh-resolution capacitance dilatometer." No additional measurement details were noted.

Cautions: Evaluated Data
"Different crystals were used for measurements along the c- and a,b-axes..." Digitized data were obtained from Figure 1 of the paper.