In this letter, we describe results obtained via laser ablation to fabricate Tl 2 Ba 2 Ca 2 Cu 3- O 10 superconducting thin films using a two-step process. We found that the zero-resistance temperatures are up to 121 K, while the onset temperatures are up to 125 K. The T c and J c are mainly determined by a non-contact new technique for high-T c films. The typical critical current density, J c , is about 106 A/cm 2 at 77 K. X-ray diffraction showed that the superconducting thin films are nearly single 2223 phase and are highly oriented.

For high temperature superconducting multichip modules and other related electronic applications, it is necessary to be able to fabricate several Y1Ba2Cu3O7–x (YBCO) layers separated by thick low dielectric constant dielectric layers. In this work, we report the successful fabrication of YBCO/YSZ/SiO2 (1–2 μm)/YSZ/YBCO multilayer structures on single crystal yttria stabilized zirconia (YSZ) substrates. In contrast to previously reported work, the top YBCO layer did not show any cracking. This is due to a technique that allows for stress relief in the SiO2 layer before the second YBCO layer is deposited. The top YBCO layer in our multilayer structure had Tc = 87 K and Jc = 105 A/cm2 (at 77 K), whereas the bottom YBCO layer had Tc = 90 K and Jc = 1.2 × 106 A/cm2 (at 77 K). We also showed that the quality of the bottom YBCO layer was preserved during the fabrication of the multilayer due to the annealing process during which O2 diffused into the YBCO, replacing the O2 lost during the deposition of the top YBCO layer.

Sr2(AlTa)O6 thin films (2000–3000 Å) have been deposited on MgO (001) substrates using pulsed laser deposition (PLD). X-ray-diffraction analysis shows that the Sr2(AlTa)O6 grows with the c axis highly oriented normal to the substrate plane and very good in-plane epitaxy. The subsequently deposited YBa2Cu3O7−x films using PLD on Sr2(AlTa)O6 buffered MgO substrates exhibit excellent epitaxial growth with a narrow rocking curve width and a small φ scan peak width. The critical temperature Tc0 of 90–92 K has been achieved reproducibly and the critical current density is over 2.7×106 A/cm2 at 77 K.

In order to build high-temperature superconductor (HTS) multichip modules (MCMs), it is necessary to grow several epitaxial layers of YBCO that are separated by thick dielectric layers without seriously affecting the quality of the YBCO layers. In this work, we have successfully fabricated YBCO/YSZ/SiO2/YSZ/YBCO structures on single-crystal LaAlO3 substrates using a combination of pulsed laser deposition for the YBCO layers and ion-beam-assisted rf sputtering to obtain biaxially aligned YSZ intermediate layers. The bottom YBCO layer had a Tc∼89 K, Jc∼7.2×105 A/cm2 at 77 K, whereas the top YBCO layer had a Tc∼86 K, Jc∼6×105 A/cm2 at 77 K. The magnetic field and temperature dependence of Jc for the YBCO films in the multilayer have been obtained. The results for each of the YBCO layers within the YBCO/YSZ/SiO2/YSZ/YBCO structure are quite similar to those for a good quality single-layer YBCO film.