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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: Improvement of the Superconducting Properties of the La2-xBaxCuO4 System (0 ≤x ≤0.15) by Low-Temperature Fluorination
Author(s): M. Cassart, E. Grivei, J.P. Issi, E. Ben Salem, B. Chevalier, C. Brisson, and A. Tressaud
Publication: Physica C Volume: 213 Issue: Not Available Year: 1993 Page(s): 327-337
Editor(s): Not Available
Publisher: Elsevier Science Publishers B.V.
Language: English
Notes: Not Available
Keywords: Material Specification, Critical Temperature, Resistivity (normal state), Thermal Conductivity, Specific Heat, Thermoelectric Power

Materials and Properties

La:21; [La(Ba)-Cu-O]
Material Specification for La:21; [La(Ba)-Cu-O] Process: Solid State Reaction
Notes: The authors cite B. Chevalier et al., Physica C, Vol. 167, 97 (1990), and summarize the procedure as follows. "The La2-xBaxCuO4 oxides were prepared by thoroughly mixing appropriate amounts of La2O3, BaCO3 and CuO powder, each 99.9% pure. The mixture was first heated in air at 950 °C for 20 h in an alumina crucible. After grinding, the powders were pressed into pellets and refired in an oxygen flow at 1100 °C for 10 h, then slowly cooled down to 450 °C and finally annealed at this temperature for 10 h. One of the La2CuO4 samples was annealed in an argon flow at 600 °C for 12 h. The fluorination treatments were made in a fluorination gas line at temperatures not exceeding 200 °C..."
Formula: La2-xBaxCuO4
Informal Name: La:21
Chemical Family: La(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 La:21; [La(Ba)-Cu-O]
Treatment Gas () x of Bax (formula units) Critical Temperature (K)
-- 0.00 0
-- 0.04 0
-- 0.08 18
-- 0.125 10
-- 0.15 33
F2 0.00 43
F2 0.04 31
F2 0.08 32
F2 0.125 33
F2 0.15 33
Measurement Method: Thermal potentiometer
The authors cite L. Piraux et al., Measurement, Vol. 5, 185 (1987), and summarize the procedure as follows. "In order to measure correctly the thermal properties, a four-probe method is needed to avoid problems associated with thermal contact resistances... In this system four heaters have been used; the first one is the sample heater (HS) which generates the temperature difference ΔT across the sample, and the three others operate as guards. The first guard (the heater guard HG) shields the sample heater, in order to reduce both heat losses arising from radiation from the heater and from conduction through the heater current and voltage leads, which are thermally anchored to the HG... In order to reduce heat losses via the thermometer wires... two other guards... are used... To reduce the heat losses by radiation from the sample surface, the sample is placed inside a small thin-walled copper box, acting as a temperature-controlled radiation shield matching the temperature profile of the sample in the direction of the sample axis... Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference profile of the sample in the direction of the sample axis. Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference... whereas at higher temperatures, two chromel constantan thermocouples T and T were used... To measure the voltage on the sample we used the two chromel wires of the two therocouples T and T ... samples (were) annealed either at 600 °C in Ar... or at 450 °C in O2... and after a treatment at 200 °C in F2 atmosphere..."

Cautions: Evaluated Data
Digitized data were obtained from Figure 8 of the paper.
Resistivity (normal state) for La:21; [La(Ba)-Cu-O]
x of Bax (formula units) Treatment () Temperature (K) Resistivity (normal state) (mΩ·cm)
0 Ar 52 84000
0 Ar 104 4100
0 Ar 147 2400
0 Ar 199 2400
0 Ar 251 2000
0 Ar 297 2000
0 Ar,F2 29 1.2
0 Ar,F2 52 24
0 Ar,F2 101 24
0 Ar,F2 157 24
0 Ar,F2 199 20
0 Ar,F2 248 24
0 Ar,F2 280 20
0 O2 3 59
0 O2 33 840
0 O2 36 3500
0 O2 98 290
0 O2 147 240
0 O2 209 200
0 O2 251 140
0 O2 294 100
0 O2,F2 42 1.0
0 O2,F2 49 5.9
0 O2,F2 101 4.9
0 O2,F2 153 5.9
0 O2,F2 202 7.0
0 O2,F2 241 5.9
0 O2,F2 277 5.9
0.08 -- 17 2.1
0.08 -- 28 3.0
0.08 -- 52 2.9
0.08 -- 105 3.3
0.08 -- 157 4.2
0.08 -- 206 5.6
0.08 -- 269 7.6
0.08 F2 17 1.1
0.08 F2 35 1.4
0.08 F2 49 1.7
0.08 F2 101 2.1
0.08 F2 150 2.8
0.08 F2 202 3.7
0.08 F2 241 4.4
0.08 F2 300 5.5
0.125 -- 10 0
0.125 -- 14 1.1
0.125 -- 31 1.2
0.125 -- 52 1.0
0.125 -- 105 1.2
0.125 -- 157 1.7
0.125 -- 202 2.1
0.125 -- 255 2.9
0.125 -- 300 3.2
0.125 F2 31 0
0.125 F2 35 0.6
0.125 F2 52 0.7
0.125 F2 105 1.0
0.125 F2 147 1.2
0.125 F2 202 1.7
0.125 F2 251 2.0
0.125 F2 300 2.3
Measurement Method: Thermal potentiometer
The authors cite L. Piraux et al., Measurement, Vol. 5, 185 (1987), and summarize the procedure as follows. "In order to measure correctly the thermal properties, a four-probe method is needed to avoid problems associated with thermal contact resistances... In this system four heaters have been used; the first one is the sample heater (HS) which generates the temperature difference ΔT across the sample, and the three others operate as guards. The first guard (the heater guard HG) shields the sample heater, in order to reduce both heat losses arising from radiation from the heater and from conduction through the heater current and voltage leads, which are thermally anchored to the HG... In order to reduce heat losses via the thermometer wires... two other guards... are used... To reduce the heat losses by radiation from the sample surface, the sample is placed inside a small thin-walled copper box, acting as a temperature-controlled radiation shield matching the temperature profile of the sample in the direction of the sample axis... Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference profile of the sample in the direction of the sample axis. Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference... whereas at higher temperatures, two chromel constantan thermocouples T and T were used... To measure the voltage on the sample we used the two chromel wires of the two therocouples T and T ... samples (were) annealed either at 600 °C in Ar... or at 450 °C in O2... and after a treatment at 200 °C in F2 atmosphere..."

Cautions: Evaluated Data
Digitized data were obtained from Figures 2 and 11 of the paper.
Thermal Conductivity for La:21; [La(Ba)-Cu-O]
x of Bax (formula units) Treatment () Temperature (K) Thermal Conductivity (W m-1 K-1)
0 Ar 5 0.25
0 Ar 10 0.98
0 Ar 30 4.4
0 Ar 48 4.2
0 Ar 100 3.8
0 Ar 300 4.2
0 Ar,F2 2.6 0.02
0 Ar,F2 9.5 0.29
0 Ar,F2 26 1.1
0 Ar,F2 51 1.3
0 Ar,F2 100 1.6
0 Ar,F2 280 2.2
0 O2 5.3 0.26
0 O2 10 0.84
0 O2 22 2.6
0 O2 39 3.8
0 O2 48 4.0
0 O2 100 3.8
0 O2 300 3.2
0 O2F2 3.5 0.075
0 O2F2 9.5 0.43
0 O2F2 30 1.7
0 O2F2 51 1.9
0 O2F2 100 2.2
0 O2F2 230 2.9
0 O2F2 240 2.9
0.08 -- 4 0.044
0.08 -- 26 0.85
0.08 -- 50 1.4
0.08 -- 103 1.8
0.08 -- 143 1.9
0.08 -- 189 2.0
0.08 -- 249 2.1
0.08 -- 299 2.2
0.08 F2 4 0.044
0.08 F2 39 1.1
0.08 F2 48 1.2
0.08 F2 103 1.8
0.08 F2 149 2.0
0.08 F2 202 2.4
0.08 F2 242 2.6
0.08 F2 266 2.8
0.125 -- 2 0.22
0.125 -- 24 1.4
0.125 -- 39 1.7
0.125 -- 59 1.5
0.125 -- 101 2.0
0.125 -- 171 2.2
0.125 -- 202 2.2
0.125 -- 253 2.3
0.125 -- 297 2.4
0.125 F2 4 0.066
0.125 F2 28 0.86
0.125 F2 85 1.7
0.125 F2 136 2.1
0.125 F2 184 2.3
0.125 F2 248 2.7
0.125 F2 297 2.9
0.125 F2 299 2.9
Measurement Method: Thermal potentiometer
The authors cite L. Piraux et al., Measurement, Vol. 5, 185 (1987), and summarize the procedure as follows. "In order to measure correctly the thermal properties, a four-probe method is needed to avoid problems associated with thermal contact resistances... In this system four heaters have been used; the first one is the sample heater (HS) which generates the temperature difference ΔT across the sample, and the three others operate as guards. The first guard (the heater guard HG) shields the sample heater, in order to reduce both heat losses arising from radiation from the heater and from conduction through the heater current and voltage leads, which are thermally anchored to the HG... In order to reduce heat losses via the thermometer wires... two other guards... are used... To reduce the heat losses by radiation from the sample surface, the sample is placed inside a small thin-walled copper box, acting as a temperature-controlled radiation shield matching the temperature profile of the sample in the direction of the sample axis... Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference profile of the sample in the direction of the sample axis. Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference... whereas at higher temperatures, two chromel constantan thermocouples T and T were used... To measure the voltage on the sample we used the two chromel wires of the two therocouples T and T ... samples (were) annealed either at 600 °C in Ar... or at 450 °C in O2... and after a treatment at 200 °C in F2 atmosphere..."

Cautions: Evaluated Data
Digitized data were obtained from Figures 4 and 12 of the paper.
Specific Heat for La:21; [La(Ba)-Cu-O]
x of Bax (formula units) Treatment () Temperature (K) Specific Heat (J kg-1 K-1)
0 Ar 57 99
0 Ar 98 194
0 Ar 155 285
0 Ar 248 375
0 Ar 276 401
0 O2 57 99
0 O2 110 220
0 O2 181 306
0 O2 229 349
0 O2 293 392
0.125 -- 5 0.1
0.125 -- 11 1.1
0.125 -- 25 17
0.125 -- 97 200
0.125 -- 290 510
0.125 F2 5 0.1
0.125 F2 11 2.2
0.125 F2 25 24
0.125 F2 97 230
0.125 F2 310 700
Measurement Method: Thermal potentiometer
The authors cite L. Piraux et al., Measurement, Vol. 5, 185 (1987), and summarize the procedure as follows. "In order to measure correctly the thermal properties, a four-probe method is needed to avoid problems associated with thermal contact resistances... In this system four heaters have been used; the first one is the sample heater (HS) which generates the temperature difference ΔT across the sample, and the three others operate as guards. The first guard (the heater guard HG) shields the sample heater, in order to reduce both heat losses arising from radiation from the heater and from conduction through the heater current and voltage leads, which are thermally anchored to the HG... In order to reduce heat losses via the thermometer wires... two other guards... are used... To reduce the heat losses by radiation from the sample surface, the sample is placed inside a small thin-walled copper box, acting as a temperature-controlled radiation shield matching the temperature profile of the sample in the direction of the sample axis... Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference profile of the sample in the direction of the sample axis. Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference... whereas at higher temperatures, two chromel constantan thermocouples T and T were used... To measure the voltage on the sample we used the two chromel wires of the two therocouples T and T ... samples (were) annealed either at 600 °C in Ar... or at 450 °C in O2... and after a treatment at 200 °C in F2 atmosphere..."

Cautions: Evaluated Data
For specific heat, no significant difference was noted between treated and untreated specimens. Digitized data were obtained from Figures 5 and 14 of the paper.
Thermoelectric Power for La:21; [La(Ba)-Cu-O]
x of Ba (formula units) Treatment () Temperature (K) Thermoelectric Power (µV/K)
0 Ar 43 889
0 Ar 82 838
0 Ar 152 702
0 Ar 204 661
0 Ar 284 624
0 Ar,F2 49 19
0 Ar,F2 109 23
0 Ar,F2 162 22
0 Ar,F2 204 20
0 Ar,F2 254 18
0 Ar,F2 284 18
0 O2 20 1.4
0 O2 30 1.9
0 O2 36 11
0 O2 40 106
0 O2 49 160
0 O2 96 346
0 O2 148 346
0 O2 214 326
0 O2 300 307
0 O2,F2 30 1.0
0 O2,F2 33 1.6
0 O2,F2 46 12
0 O2,F2 49 16
0 O2,F2 102 24
0 O2,F2 158 27
0 O2,F2 208 29
0 O2,F2 284 31
0.08 -- 47 50
0.08 -- 93 82
0.08 -- 144 98
0.08 -- 188 108
0.08 -- 251 116
0.08 -- 299 112
0.08 F2 41 32
0.08 F2 77 53
0.08 F2 153 70
0.08 F2 205 78
0.08 F2 245 81
0.08 F2 271 82
0.125 -- 25 7
0.125 -- 39 7
0.125 -- 56 35
0.125 -- 96 47
0.125 -- 151 52
0.125 -- 207 51
0.125 -- 255 51
0.125 -- 299 48
0.125 F2 49 30
0.125 F2 100 35
0.125 F2 163 34
0.125 F2 208 32
0.125 F2 252 30
0.125 F2 300 27
Measurement Method: Thermal potentiometer
The authors cite L. Piraux et al., Measurement, Vol. 5, 185 (1987), and summarize the procedure as follows. "In order to measure correctly the thermal properties, a four-probe method is needed to avoid problems associated with thermal contact resistances... In this system four heaters have been used; the first one is the sample heater (HS) which generates the temperature difference ΔT across the sample, and the three others operate as guards. The first guard (the heater guard HG) shields the sample heater, in order to reduce both heat losses arising from radiation from the heater and from conduction through the heater current and voltage leads, which are thermally anchored to the HG... In order to reduce heat losses via the thermometer wires... two other guards... are used... To reduce the heat losses by radiation from the sample surface, the sample is placed inside a small thin-walled copper box, acting as a temperature-controlled radiation shield matching the temperature profile of the sample in the direction of the sample axis... Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference profile of the sample in the direction of the sample axis. Below 77 K, we use an Au(Fe)/chromel differential thermocouple for measuring the temperature difference... whereas at higher temperatures, two chromel constantan thermocouples T and T were used... To measure the voltage on the sample we used the two chromel wires of the two therocouples T and T ... samples (were) annealed either at 600 °C in Ar... or at 450 °C in O2... and after a treatment at 200 °C in F2 atmosphere..."

Cautions: Evaluated Data
Digitized data were obtained from Figures 3 and 9 of the paper.