Possibility of Nd:YAG-PLD Method for Fabricating REBCO Coated Conductors

A Nd:YAG (neodymium-doped yttrium aluminum garnet) laser is environmentally safe, due to the absence of any poisonous or hazardous gases, and also economical, without the need for expensive gases. We can thus expect a safe and low cost REBa₂Cu₃Oy (REBCO)-coated conductor fabrication process by using an Nd:YAG laser. We investigated the fabrication of YBa₂Cu₃Oy (YBCO) films using a PLD method with a fourth harmonic Nd:YAG laser. The YBCO films showed good superconducting properties; for example, on SrTiO₃ single crystalline substrates, T_c and J_c were about 90 K and 2.5 MA/cm², respectively, at 77 K. In order to enhance J_c in magnetic fields, BaSnO₃ was doped into YBCO films by means of a combinatorial Nd:YAG-PLD method. The combinatorial method enabled the growth and study of a library of samples ranging from pure-YBCO to BSO-doped-YBCO. We demonstrated rapid optimization of BaSnO₃ content by the combinatorial method and concluded that the optimal BSO content was around 3.6 wt%. In addition, in order to enhance material yield of the Nd:YAG-PLD method, we optimized the oxygen pressure and distance between the target and substrate. On a substrate with dimensions of 10 × 10 mm², the material yield of a YBCO film reached about 19.0%. These results suggest that the Nd:YAG-PLD method is promising for forming YBCO-coated conductors.