How to Control the Gd211 Particles and Enhance the Levitation Force of Single Domain GdBCO Bulks Prepared by the Gd+011 TSIG Method

In order to control and refine Gd211 particle size in GdBCO bulks, two group of single domain GdBCO bulk superconductors have been prepared with different solid phase pellets sintered at different temperature (T) and times by the Gd+011 TSIG method. The results of the first group of single domain GdBCO bulks indicate that: the average size of Gd211 particles in precursor solid phase pellets increase with T increasing up to 1200 °C; the density of the precursor solid phase pellets increases with the increasing of T when T is larger than 950 °C, but lower than that of the as-pressed pellets when T less than 1000 °C; the average size of Gd211 particles in the single domain GdBCO bulks decreases first and increases then with the increasing T; the maximum levitation force is obtained in the sample with a relatively larger size of Gd211 particles and higher density. The second group of samples has also been prepared with the solid phase pellets sintered at 1000 °C but with different times, the results indicate that: the largest levitation force is about 38% higher than that of the best samples mentioned above. The results are discussed in detail.