Material Specification for Nd:21; [Nd(Ce,Sr)-Cu-O]
Process: Solid State Reaction
Notes: "Samples of the... system Nd2-x-yCexSryCuO4-δ,... have been prepared by a standard solid-state reaction technique, using stoichiometric amounts of Nd2O3, CeO2, SrCO3, and CuO, each of 99.9% or higher purity. Mixed powders have been calcinated by 950 °C in air for 24 h and fired twice at 1040 °C in flowing O2 (purity 99.998%) for 15 h with intermediate regrindings. After this, samples were again reground, pressed into pellets, and sintered twice at 1140 °C for a total of 80 h in flowing O2... In order to achieve superconductivity with a Tc of about 25 K an oxidation step at temperatures between 900 °C and 400 °C for more than 100 h was necessary after final sintering procedure... Samples of the "infinite-layer compound" Sr1-xNdxCuO2-δ have been prepared from citrate-nitrate precursors optimized with respect to a homogeneous distribution of the corresponding cations on a molecular level. Decomposition and removal of the organics were done at temperatures around 600 °C and 1000 °C. The resulting black powders were then sintered in a modified belt press using high temperatures by simultaneously applying high quasihydrostatic pressure. Typical parameters are T=1400 °C and p=(4 GPa = 40 kbar) with a second annealing step at 1100 °C and the same pressure. A slightly reducing atmosphere generated by Pt crucibles was necessary to guarantee the incorporation of Nd into the structure. The samples were then quenched down to room temperature before releasing the pressure."
Formula: Nd1.4Ce0.2Sr0.4CuO4-x
Informal Name: Nd:21
Chemical Family: Nd(Ce,Sr)-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Hall Coefficient for Nd:21; [Nd(Ce,Sr)-Cu-O]
| Temperature (K) |
Hall Coefficient (mm3 /C) |
| 50 |
1.40 |
| 75 |
1.54 |
| 100 |
1.70 |
| 125 |
1.83 |
| 150 |
1.88 |
| 175 |
1.88 |
| 200 |
1.79 |
| 225 |
1.77 |
Measurement Method: Hall effect method
"For Hall-effect measurements samples were thinned to platelets with a thickness of about 0.2 mm. Gold contacts were evaporated on the samples and annealed for several hours at 400 °C in Ar or O
2 flow... After that, wires were soldered onto the contacts using Wood's metal... Values of R
measured for various samples from different preparation batches are equal within an error of 5-10%."
Cautions: Evaluated Data
Digitized data were obtained from Figure 12 of the paper.
Critical Flux Density Hc1 for Nd:21; [Nd(Ce,Sr)-Cu-O]
| Temperature (K) |
Crit.Mag.Flux Density Hc1 (mT) |
| 2.7 |
4.2 |
| 3.7 |
4.4 |
| 4.9 |
4.3 |
| 6.1 |
4.1 |
| 8.3 |
3.9 |
| 10.3 |
3.9 |
| 14.3 |
3.5 |
| 18.4 |
2.8 |
| 22.4 |
2.0 |
| 24.3 |
1.5 |
| 26.1 |
0.0 |
| 29.0 |
0.0 |
Measurement Method: SQUID magnetometer
"... the magnetic susceptibility (was) measured in a Quantum Design superconducting quantum interference device (SQUID) magnetometer model MPMS... (field cooled and zero-field cooled)... The determination of the lower critical field was done in two different ways, giving the same results... The first method... was to determine the first deviation of the field-dependent magnetization M(H) from a linear behavior... A second, independent method is the determination of the magnetic field H, beyond which time-dependent relaxation in M(H,t) starts."
Cautions: Evaluated Data
Digitized data were obtained from Figure 4 of the paper.
Material Specification for Sr:11; [Sr(Nd)-Cu-O]
Process: Solid State Reaction
Notes: "Samples of the... system Nd2-x-yCexSryCuO4-δ,... have been prepared by a standard solid-state reaction technique, using stoichiometric amounts of Nd2O3, CeO2, SrCO3, and CuO, each of 99.9% or higher purity. Mixed powders have been calcinated by 950 °C in air for 24 h and fired twice at 1040 °C in flowing O2 (purity 99.998%) for 15 h with intermediate regrindings. After this, samples were again reground, pressed into pellets, and sintered twice at 1140 °C for a total of 80 h in flowing O2... In order to achieve superconductivity with a Tc of about 25 K an oxidation step at temperatures between 900 °C and 400 °C for more than 100 h was necessary after final sintering procedure... Samples of the "infinite-layer compound" Sr1-xNdxCuO2-δ have been prepared from citrate-nitrate precursors optimized with respect to a homogeneous distribution of the corresponding cations on a molecular level. Decomposition and removal of the organics were done at temperatures around 600 °C and 1000 °C. The resulting black powders were then sintered in a modified belt press using high temperatures by simultaneously applying high quasihydrostatic pressure. Typical parameters are T=1400 °C and p=(4 GPa = 40 kbar) with a second annealing step at 1100 °C and the same pressure. A slightly reducing atmosphere generated by Pt crucibles was necessary to guarantee the incorporation of Nd into the structure. The samples were then quenched down to room temperature before releasing the pressure."
Formula: Sr0.85Nd0.15CuO2-x
Informal Name: Sr:11
Chemical Family: Sr(Nd)-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form:
Critical Flux Density Hc1 for Sr:11; [Sr(Nd)-Cu-O]
| Temperature (K) |
Crit.Mag.Flux Density Hc1 (mT) |
| 4.3 |
1.5 |
| 6.0 |
1.4 |
| 8.2 |
1.4 |
| 10.4 |
1.2 |
| 13.3 |
1.2 |
| 16.2 |
0.9 |
| 19.4 |
0.8 |
| 22.3 |
0.7 |
| 25.4 |
0.4 |
| 29.3 |
0.2 |
Measurement Method: SQUID magnetometer
"... the magnetic susceptibility (was) measured in a Quantum Design superconducting quantum interference device (SQUID) magnetometer model MPMS... (field cooled and zero-field cooled)... The determination of the lower critical field was done in two different ways, giving the same results... The first method... was to determine the first deviation of the field-dependent magnetization M(H) from a linear behavior... A second, independent method is the determination of the magnetic field H, beyond which time-dependent relaxation in M(H,t) starts."
Cautions: Evaluated Data
Digitized data were obtained from Figure 4 of the paper.
