Material Specification for Tl:2212; [Tl-Ba-Ca-Cu-O]
Process: Solid State Reaction
Notes: "Epitaxial... films were prepared on a single side of... (5.1 cm) diam LaAlO3 wafers through a standard two-step process. BaCaCuO precursor films of thickness 0.58±0.05 µm were deposited by off-axis magnetron sputtering. The amorphous precursor films were annealed in air at 850 °C in the presence of a powder mixture of Tl2Ba2Ca2Cu3O10 and Tl2O3. Volatile Tl2O from the powder reacts with the precursor film to form the Tl2Ba2CaCu2O8 phase... The films were patterned using standard photolithographic techniques. Poly methyl methacrylate (PMMA) resist (KTI 497 K) was spun onto the wafer and baked at 170 °C. Then positive photoresist (Shipley 1400-17) was spun onto the wafer and baked at 90 °C. Photolithographic transfer from the chromium contact mask to the wafer was performed with UV light. The positive photoresist was developed, and the wafer was rinsed in distilled water. At this point, the remaining positive photoresist serves as a contact mask for the underlying PMMA. Following plasma descumming, deep UV radiation was used to unlink the unprotected PMMA, which was then dissolved with toluene. Ion milling of the exposed Tl2Ba2CaCu2O8 film was carried out with a 400 eV argon ion beam at normal incidence. The remaining PMMA and photoresist was removed by plasma etching. Photoresist was spun onto the wafer, the wafer was diced, and the photoresist was chemically stripped in acetone and isopropanol. Silver pads were deposited by sputter deposition through shadow masks, followed by annealing in flowing oxygen at 500 °C... The HTS chips were then mounted on printed circuit boards, and the silver contacts were attached to the board through wirebonding gold wire."
Formula: Tl2Ba2CaCu2O8
Informal Name: Tl:2212
Chemical Family: Tl-Ba-Ca-Cu-O
Chemical Class: Oxide
Structure Type: Polycrystalline
Manufacturer: In House
Commercial Name: In House
Production Date:
Lot Number:
Production Form: Thin Film
Critical Temperature for Tl:2212; [Tl-Ba-Ca-Cu-O]
| Critical Temperature (K) |
| 105 ± 1 |
Measurement Method: Four-probe method
"... measurements were carried out in zero external magnetic field by the four-point probe technique using a Keithley 220 programmable current source for low currents, a Keithley 228 current source for high currents, and a Keithley 182 digital voltmeter. Temperature was measured by a Lakeshore semiconductor diode thermometer. Voltage drop was measured as a function of current. Calculations of J
c were carried out using the standard criteria E
c=1.0 µV/cm."
Cautions: Evaluated Data
Critical Current Density for Tl:2212; [Tl-Ba-Ca-Cu-O]
| Temperature (K) |
Critical Current Density (kA/cm2) |
| 20 |
10400 |
| 50 |
6060 |
| 70 |
3160 |
| 80 |
1820 |
| 95 |
430 |
Measurement Method: Four-probe method
"... measurements were carried out in zero external magnetic field by the four-point probe technique using a Keithley 220 programmable current source for low currents, a Keithley 228 current source for high currents, and a Keithley 182 digital voltmeter. Temperature was measured by a Lakeshore semiconductor diode thermometer. Voltage drop was measured as a function of current. Calculations of J
c were carried out using the standard criteria E
c=1.0 µV/cm."
Cautions: Evaluated Data
