Over the course of the past 2-3 weeks, we have been making a second batch of superconductor pellets. It is somewhat following the "more is better" philosophy that we have adopted in developing this levitating vehicle. Having more pellets allows us to make more vehicles, with possibly more pellets in each vehicle, improving their levitating power.
We made a few changes to the synthesis procedure, but one appears to be most significant. For the first preparation we used a long-cylindrical boat crucible made of alumina. The pellets leaned against the sides of the boat. We were pleased with the levitating results that we observed, but the diffraction data was a little messy. We theorized that the aberrant peaks were likely due to alumina contaminating the pellets. To avoid this, we used a more upright alumina crucible, and stacked the pellets so that they would not touch the sides.
This second batch levitates amazingly higher than our previous preparation, and the diffraction data is much cleaner, matching the reference scans with much more precision. Below are two pictures, before and after. The pictures were not taken at exactly the same angle and distance, but I think the difference in levitating ability is clear.
Another picture of the levitation with the new batch of YBCO: