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Thick films of YBa2Cu3O7-δ (YBCO) have been fabricated on yittria stabilized zirconia (YSZ) by using the screen printing method. In order to substantially increase Jc, it is clear that a method has to be found by which the number of weak links such as second phases and high angle grain boundaries can be reduced. In this paper, we report a promising method employing a seed crystal of RBa2Cu3O7-δ (R= Gd, Sm and Nd) by which large area of YBCO crystal can be fabricated in the thick film.

Since High-Tc superconductors such as Y-system and Bi-system show perfect diamagnetism at above 90 K, it is expected that a magnetic field will be shielded by superconductors cooled with liquid nitrogen. In this study, magnetic shielding effect of superconducting YBaCuO disks prepared by melt processes was measured at 77K. The results indicate that disk samples with ~16 mm in diameter and ~ 1 mm in thickness can reduce an external magnetic field in intermediate field range, but that the magnetic flux comes in through grainboundaries and cracks of the sample.

A method of manufacturing potassium niobate single crystal thin film on a single crystal substrate that epitaxially grows orthorhombic potassium niobate single crystal at a temperature near room temperature at a high deposition rate. A surface acoustic wave element, frequency filter, frequency oscillator, electronics circuit, and electronic device employ the thin film manufactured by the method, and are high in k 2 , wideband, downsized, and economical in power consumption. The method includes the steps of coating liquid drops of a potassium niobate solution on a SrTiO 3 single crystal substrate by a liquid drop emission method, and precipitating potassium niobate single crystal layer by epitaxial growth from the liquid drops.

A surface acoustic wave element includes a single crystal substrate; a buffer layer formed by a crystal film that is formed on top of the single crystal substrate; and a piezoelectric thin film having a hexagonal system or a trigonal system crystal structure that is formed on top of the buffer layer. The surface acoustic wave element has an improved performance by improving the film quality of the piezoelectric thin film. In addition, because a semiconductor device can be formed on the single crystal substrate, the surface acoustic wave element can be integrated with the semiconductor device. Moreover, leakages of surface acoustic waves into the single crystal substrate are prevented. There are also provided a frequency filter, an oscillator, an electronic circuit, and an electronic instrument that are provided with this surface acoustic wave element.

Magnetization properties by a pulsed magnetic field were studied in YBaCuO superconductors prepared by the Melt-Powder-Melt-Growth (MPMG) process. The sample size was 10 mm × 10 mm × 1 mm. A pulsed magnetic field of up to 2.3 T was applied perpendicular to the sample surface at 77 K. Two-dimensional distributions of the trapped magnetic field over the YBaCuO sample surface were measured at 77 K by a scanning Hall sensor. A maximum magnetic field of 0.15 T was trapped. The maximum trapped magnetic field increased with an increasing applied magnetic field, and showed a peak. Then the trapped field decreased with a further increasing pulsed magnetic field.

Flux pinning properties were studied for NdBa 2 Cu 3 O 7−d (Nd123) single crystals flux-grown in low oxygen partial pressures. In the high temperature ( T ) region roughly above 70 K, apparent fishtail peaks were commonly observed on the magnetization hysteresis ( M-H ) curves or the critical current density vs magnetic field ( J c -B curves). For this high T region, while J c (B,T ) curves in low B followed an empirical equation from Matsushita et al. [1], those in high B obviously deviated from the equation, however, those could be well scaled to a single curve by plotting the normalized flux pinning force density f p vs the reduced B/B irr where B irr is the irreversibility field, indicating that dominant pinning mechanisms are different between low and high B region.

KNbO3 epitaxial thin films were fabricated on sapphire r-plane substrates with an MgO buffer layer by pulsed laser deposition. X-ray diffraction measurements revealed that both MgO and KNbO3 were epitaxially grown on the Al2O3 (1-102) substrate with an orientation relationship as KNbO3 (100)pc/MgO (100)/Al2O3 (1-102) (out-of-plane) and KNbO3 [010]pc//MgO [010]//Al2O3 [11-20] (in-plane), although both MgO and KNbO3 were tilted 6–9° with respect to the substrate surface. Raman scattering measurements revealed that the KNbO3 film was composed of the orthorhombic ferroelectric phase, and that the (010)ortho (Y) domain, in which the polarization axis was parallel to the substrate surface, was dominant. The present study enables the production of KNbO3 epitaxial thin-film wafers, which correspond to Y-cut KNbO3 single crystals with a large electromechanical coupling coefficient (k 2=0.53), for surface acoustic wave propagation.

REBa 2 Cu 3 O y (RE: Nd, Sm) superconductors exhibit relatively high J c values even at 77K when melt-processed in a reduced oxygen atmosphere. The J c values of these superconductors are higher than those of melt processed YBa 2 Cu 3 O y with fine Y 2 BaCuO 5 inclusions in a high field region. The irreversibility field with H ∥ c axis was dramatically increased to 8T at 77K. We believe that flux pinning in these superconductors is ascribable to a finely distributed RE(Ba 1−x , RE x ) 2 Cu 3 O y phase in a good superconductive matrix.

Conductive SrRuO3 films were deposited on {001} Si substrates by pulsed-laser deposition using SrO as buffer layers. The microstructure and orientation relationships (ORs) of the constituting layers were investigated by X-ray diffraction, transmission electron microscopy, high-resolution electron microscopy and energy dispersive X-ray spectroscopy. Good epitaxial growth of SrO and SrRuO3 films on the Si substrates was achieved. Multiple domains were formed in the SrRuO3 films. The domain boundaries were nearly perpendicular to the interface between the SrRuO3 films and the SrO buffer layers. Three ORs among Si, SrO and SrRuO3 were observed, indicating a new OR between Si and SrO.

The effects of various oxygen partial pressures (P O2) during melt processing on the superconducting properties of fabricated NdBa2Cu3O y (Nd123) superconductors have been systematically investigated. Unlike in air or O2, samples melt-processed in reduced oxygen atmospheres exhibited unprecedentedly high T c's of 95–96 K with a sharp superconducting transition. Especially, for a sample melt-processed in 0.1% O2 in Ar, the magnetization hysteresis ( M-H ) loop was kept open up to 7 T at 77 K and for the field parallel to the c-axis of the sample (H//c), implying that very effective flux pinning can be achieved in high magnetic fields.

REBa2Cu3O y superconductors with rare earth (RE) ions with large radii (RE: La, Nd, Sm) exhibit relatively low T c due to the presence of RE-Ba solid solution. We have found that this solid solution can be suppressed if these superconductors are melt processed in a reduced oxygen atmosphere. We have also found that critical current densities of these superconductors are higher than those of melt processed YBa2Cu3O y with fine Y2BaCuO5 inclusions in a high field region. The irreversibility line was also shifted toward the higher H-T region. We believe that flux pinning in these superconductors is ascribable to a finely distributed RE(Ba1- x , RE x )2Cu3O y phase in a good superconductive matrix.