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The study explains the surface morphology and microstructure of thick Y[Ba.sub.2][Cu.sub.3][O.sub.7-[delta]] (YBCO) films prepared on vicinal r-cut sapphire buffered with Ce[O.sub2]. These sapphire substrates can be easily used for practical applications of cuprate superconductors.

Microcrack-free thick YBa2Cu3O7-δ (YBCO) films were successfully fabricated by pulsed laser deposition on deliberately miscut A12O3 (1_102) (5.22° off towards [11_20]) buffered with CeO2. Characterization of the films revealed a porous morphology, consisting of interconnected islands and deep holes (pores). The microstructure of the YBCO films was further investigated by cross-section (cut along both A12O3 [_1101] and [11_20]) transmission electron microscopy (TEM). No apparent interface reaction is seen for all the TEM observations. A high density of linear defects aligned near c-axis are frequently observed. All the defects are initiated from the YBCO/CeO2 interface, indicating the importance of the microstructure of the CeO2 buffer layer and the sapphire substrate for the growth of YRCO. In addition, numerous small stacking faults lying in the a - b-plane of YBCO were produced by the linear defects. The high density of the growth-induced defects may act as strong pinning centers in YBCO films and therefore increase Jc of the film. [ABSTRACT FROM AUTHOR]

Stoichiometric YBa2Cu3O7-δ (YBCO) films were fabricated by pulsed laser deposition on deliberately miscut Al2O3 (1...102) buffered with CeO2. Atomic force microscopy observations demonstrated that 600 nm-thick YBCO films were microcrack-free. Characterization of the films revealed a porous morphology, consisting of interconnected islands and deep holes (pores). This feature is considered as one of the sources contributing to the strain-relieving mechanism responsible for the increase in film thickness without microcracking. We observed Tc = 90±0.5K, Jc(77.3K, 0 T) = 1.5 - 2.0 × 106 A/cm², and Jct(77.3 K, 0 T) ∼ 120 A/cm. In addition, this new approach, using the deliberately miscut sapphire as a substrate for YBCO, is also applicable to other kinds of deposition techniques. [ABSTRACT FROM AUTHOR]

Microcrack-free thick YBa2Cu3O7-δ (YBCO) films were successfully fabricated by pulsed laser deposition on deliberately miscut A12O3 (1_102) (5.22° off towards [11_20]) buffered with CeO2. Characterization of the films revealed a porous morphology, consisting of interconnected islands and deep holes (pores). The microstructure of the YBCO films was further investigated by cross-section (cut along both A12O3 [_1101] and [11_20]) transmission electron microscopy (TEM). No apparent interface reaction is seen for all the TEM observations. A high density of linear defects aligned near c-axis are frequently observed. All the defects are initiated from the YBCO/CeO2 interface, indicating the importance of the microstructure of the CeO2 buffer layer and the sapphire substrate for the growth of YRCO. In addition, numerous small stacking faults lying in the a - b-plane of YBCO were produced by the linear defects. The high density of the growth-induced defects may act as strong pinning centers in YBCO films and therefore increase Jc of the film. [ABSTRACT FROM AUTHOR]

Stoichiometric YBa2Cu3O7-δ (YBCO) films were fabricated by pulsed laser deposition on deliberately miscut Al2O3 (1...102) buffered with CeO2. Atomic force microscopy observations demonstrated that 600 nm-thick YBCO films were microcrack-free. Characterization of the films revealed a porous morphology, consisting of interconnected islands and deep holes (pores). This feature is considered as one of the sources contributing to the strain-relieving mechanism responsible for the increase in film thickness without microcracking. We observed Tc = 90±0.5K, Jc(77.3K, 0 T) = 1.5 - 2.0 × 106 A/cm², and Jct(77.3 K, 0 T) ∼ 120 A/cm. In addition, this new approach, using the deliberately miscut sapphire as a substrate for YBCO, is also applicable to other kinds of deposition techniques. [ABSTRACT FROM AUTHOR]