微量Co^(3+)掺杂对GdBCO薄膜结构及超导性能的影响

Effect of dilute Co^(3+) doping on structure and superconducting properties of GdBCO thin films

采用自主研发的无氟高分子辅助金属有机物沉积(FF-PAMOD)法在LaAlO_(3)单晶基底上制备微量Co^(3+)掺杂的GdBCO薄膜,研究不同掺杂量对薄膜结构和超导性能的影响。结果表明,掺杂量x为0.001的薄膜(GdBa_(2)Cu_(3-x)CoxO_(7-z))具有更好的c轴织构和更加平整致密的表面微结构,以及在77 K自场具有最高的临界电流密度(Jc)。此外,与纯样相比,该掺杂样品(x=0.001)在磁场下显示出更高的Jc(77 K, 30 K),这可能是Co^(3+)掺杂对薄膜外延生长的促进和掺杂引入的钉扎中心共同作用的结果。

Dilute Co^(3+) doped GdBCO thin films were prepared on LaAlO3 single crystal substrates by self-developed fluorine-free polymer-assisted metal organic deposition(FF-PAMOD) method. The effect of different doping levels on the structure and superconducting properties of the films were investigated. The results show that the film with doping level x of 0.001(GdBa_(2)Cu_(3-x)CoxO_(7-z)) has better c-axis texture, smoother and denser surface microstructure as well as the highest critical current density(Jc) at 77 K and self-field. In addition, compared with the pure sample, this doped sample(x=0.001) shows higher Jc values under magnetic field at 77 K and 30 K, which may be attributed to the promotion of film’s epitaxial growth and introduction of effective flux pinning centers by Co^(3+) doping.