Hts Logo

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: Irreversibility Line and Critical Currents in Oxygen Deficient YBa2Cu3Ox Ceramics
Author(s): J. Vanacken, E. Osquiguil, and Y. Bruynseraede
Publication: Physica C Volume: 183 Issue: Not Available Year: 1991 Page(s): 163-166
Editor(s): Not Available
Publisher: Elsevier Science Publishers B.V.
Language: English
Notes: Not Available
Keywords: Material Specification, Critical Temperature, Irreversibility Field

Materials and Properties

Y:123; [Y-Ba-Cu-O]
Material Specification for Y:123; [Y-Ba-Cu-O] Process: Solid State Reaction
Notes: "Samples were prepared using dry standard powder techniques. The final sintering process was performed on pressed cylindrical pellets, 3 mm diam., and 2.7 mm in thickness. The quality of the samples was confirmed by X-ray difffraction indicating no crystalline impurity phases. Oxygen deficient YBa2Cu3Ox has been prepared using the equilibrium P -T phase diagram, starting in a reduced oxygen atmosphere of (1333 Pa = 10 torr) at the temperature T (x) appropriate to obtain a desired oxygen content x. Equilibrium was assured when the pressure of (1333 Pa = 10 torr) at T (x) was constant in time (usually 2 h for the low-x materials). The sample was then cooled down from T (x) while the pressure was decreased in order to follow the equilibrium P -T phase line."
Formula: YBa2Cu3Ox
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]
x of Ox (formula units) Critical Temperature (K)
7 89.4
6.85 75.5
6.7 58
6.6 39
Measurement Method: SQUID magnetometer
"The magnetic properties were studied using a commercial SQUID (MPMS system, Quantum Design). Special attention was given to keep the measured samples in the homogeneous region of the magnetic field (ΔH/H < 0.19%), and to assure absence of temperature hysteresis. A typical measurement proceeds as follows. After inserting the sample in the MPMS system, the whole sample room was thoroughly flushed at a temperature above 150 K, to assure no paramagnetic oxygen signals during the measurements. Then the remanent field was sweeped out and the sample was placed in the middle of the magnet to assure a near zero field (less than 0.1 mT = 1 G). Finally the sample was cooled to 5 K. After a waiting time of approximately 60 min, the field was set, taking into account that no overshoot occurred. Then the data at increasing temperature were taken, with a resolution of 0.5 K, near the irreversible temperature (T ), and 0.1 K near the second critical temperature T . The measuring time constant below the irreversible temperature is (dT/dt)... 0.15 K/min. After these zero-field cooled (ZFC) measurements, the temperature of the system was decreased, without changing the field (FC). Special care was taken to avoid undercooling and temperature gradients between sample and thermometer. The irreversibility temperature T was determined as that temperature where the difference between the FC and ZFC data was larger then the measuring error (about 2%)."

Cautions: Evaluated Data
Digitized data were obtained from Figure 3 of the paper.
Irreversibility Field for Y:123; [Y-Ba-Cu-O]
x of Ox (formula unit) Temperature (K) Irreversibility Field (T)
7 89 0.01
7 88 0.05
7 87 0.10
7 85 0.26
7 83 0.52
7 82 0.73
7 80 1.03
7 75 2.04
7 71 3.30
6.85 75 0.01
6.85 74 0.05
6.85 72 0.10
6.85 69 0.23
6.85 65 0.50
6.85 62 0.70
6.85 45 2.00
6.85 42 2.62
6.70 57 0.01
6.70 55 0.06
6.70 53 0.10
6.70 50 0.27
6.70 44 0.54
6.70 39 0.77
6.70 36 1.02
6.70 29 1.54
6.70 23 2.69
6.6 38 0.01
6.6 36 0.05
6.6 33 0.10
6.6 28 0.25
6.6 22 0.50
6.6 18 0.76
6.6 14 1.00
6.6 11 1.50
Measurement Method: SQUID magnetometer
"The magnetic properties were studied using a commercial SQUID (MPMS system, Quantum Design). Special attention was given to keep the measured samples in the homogeneous region of the magnetic field (ΔH/H < 0.19%), and to assure absence of temperature hysteresis. A typical measurement proceeds as follows. After inserting the sample in the MPMS system, the whole sample room was thoroughly flushed at a temperature above 150 K, to assure no paramagnetic oxygen signals during the measurements. Then the remanent field was sweeped out and the sample was placed in the middle of the magnet to assure a near zero field (less than 0.1 mT = 1 G). Finally the sample was cooled to 5 K. After a waiting time of approximately 60 min, the field was set, taking into account that no overshoot occurred. Then the data at increasing temperature were taken, with a resolution of 0.5 K, near the irreversible temperature (T ), and 0.1 K near the second critical temperature T . The measuring time constant below the irreversible temperature is (dT/dt)... 0.15 K/min. After these zero-field cooled (ZFC) measurements, the temperature of the system was decreased, without changing the field (FC). Special care was taken to avoid undercooling and temperature gradients between sample and thermometer. The irreversibility temperature T was determined as that temperature where the difference between the FC and ZFC data was larger then the measuring error (about 2%)."

Cautions: Evaluated Data
Digitized data were taken from Figure 3 of the paper.