High $J_{\rm c}$ ${\hbox {GdBa}}_{2}{\hbox {Cu}}_{3}{\hbox {O}}_{7-\delta }$ Coated Conducto

High quality GdBa₂Cu₃O_7-δ (GdBCO) coated conductors (CCs) were successfully fabricated on CeO₂-buffered IBAD MgO template by pulsed laser deposition (PLD). With the same energy density of 2 J/cm², laser frequency of 8 Hz, and oxygen pressure of 300 mTorr, both target-to-substrate distance (D_ts) and substrate temperature (T_s) were systematically varied from 5.5 to 4.0 cm at T_s of 780 °C and from 760 to 820 °C at D_ts of 4.5 cm, respectively, to investigate their effects on the grain alignment, microstructure, and superconducting properties of GdBCO films. Biaxially aligned GdBCO films without a-axis oriented GdBCO grains could be deposited at T_s higher than 780 °C and D_ts shorter than 5.0 cm. At T_s of 760 °C, a small amount of a-axis oriented and 45^° misaligned GdBCO grains was formed. The in-plane textures of GdBCO films were gradually improved when D_ts decreased, while those were first improved with increasing T_s up to 800 ^°C and then degraded at 820 °C. The highest critical current density (J_c) of 3.9 MA/cm² and critical current (I_c) of 195 A/cm-width (77 K, self-field) were achieved from the 500 nm GdBCO film deposited at 800°C with D_ts of 4.5 cm . The J_c values of GdBCO films were found to be sensitive to the in-plane texture and also to the presence of a -axis oriented grains and 45° misaligned grains.