The effect of Gd<sub>2</sub>Ba<sub>4</sub>CuNbO<sub>y</sub> doping on the properties of single domain GdBCO bulk superconductors

Abstract

Single domain GdBCO bulk superconductors, with compositions of GdBa 2 Cu 3 O 7-δ (Gd123):Gd 2 BaCuO 5 (Gd211): Gd 2 Ba 4 CuNbO y (GdNb2411) =1:(0.4-x):x, (x=0, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16), have been successfully fabricated by the top-seeding melt texture growth process (TSMTG). The effect of the different doping amounts of GdNb2411 on the growth morphology and the magnetic levitation force properties of single domain GdBCO bulk superconductors has been investigated. The results show that single domain GdBCO bulk samples can be fabricated within the scope of the doping, and the surface morphologies of the samples are closely related to the doping content x. It is of a smooth faced plane and four clear radius for the samples with x≤0.06 mol, but it is of a wrinkle surface for the samples with x≥0.08mol and the single domain area is observed to reduce with the increasing of x. The test results of the magnetic levitation force of the samples show that the levitation force of samples increases first and then decreases with the increasing of x, the largest levitation force of 25 N is obtained in the samples with x=0.06 mol. The results is very important for study in flux pinning of nanoparticles and further improvement in the properties of GdBCO bulk superconductors.