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Ultrahigh-Jc YBa2Cu3O7-x (YBCO) films have been successfully fabricated by the metalorganic deposition method using a trifluoroacetate coating solution which is prepared by a newly developed purification technique, the solvent-into-gel (SIG) method. The prepared pure coating solution has less than 0.25% impurities and has a wide flexibility in process conditions to obtain high-Jc YBCO film. Using this feature, we have successfully formed 50 mm diameter YBCO films, which have a critical current density over 10 MA cm-2 (77 K, 0 T) on LaAlO3 single crystalline substrates.

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Porous Li 0:06 (Na 0:5 K 0:5 ) 0:94 NbO 3 (LNKN-6) ceramics with different pore volumes have been prepared using preceramic powder and phenol resin fiber (KynolÔ) as a pore former. It was confirmed that the porous ceramics synthesized by the ''twostage firing method'' suppressed the loss of alkali elements from the porous body during heat treatment. The porous LNKN-6 ceramics were then converted to LNKN-6/KNbO 3 composites through soaking and heat treatment using a sol-gel precursor source composed of KNbO 3 to form 3 -3-type composites. The microstructure, dielectric, and piezoelectric properties of the porous LNKN-6 ceramics and LNKN-6/KNbO 3 composites were characterized and compared. The LNKN-6/KNbO 3 composites had a hollow structure whose pores in the region near the surface were filled and coated with KNbO 3 precipitates; however, a large amount of residual air was trapped in the pores inside the composites. As a result, the LNKN-6/KNbO 3 composites fabricated using 30 vol % KynolÔ showed an enhanced piezoelectric voltage output coefficient (g 33 ) of 63:0 Â 10 À3 VÁm/N, compared with monolithic LNKN-6 ceramics having a g 33 of 30:2 Â 10 À3 VÁm/N.