I have not posted in a few days, and the information of this post is actually from last week as I am writing this on the 16th.
Due to the power outages at UCSB caused by the Goleta wildfires, there has not been much lab equipment available. All furnaces were turned off, which makes since because thermal cycling (turning power on and off) is not necessarily the best way to run a solid-state reaction.
My research partner and I spent most of these days working on our PowerPoint presentations that we must produce as a part of our program.
However, the one advance that we made on these days came out of the line of thought: "If a track that is three-wide is better than two-wide, then a track that is four-wide must be better than three-wide. This turned out to be true. Our newest track design is four magnets wide. We tested the movement along both a straight and curved track. Again, the maximum curve had a distance between outer magnets of about 3-5 mm.
By Friday, we felt relatively secure that there would be no more power outages, so we set our second batch of pellets to anneal in the tube furnace (48 hr @ 940 degrees C). We made one change to the reaction conditions. Rather than using an alumina boat (long and thin) we used a crucible. This allowed us to stack the pellets and by carefully sliding the crucble into the tube, the pellets did not touch the side of the crucible, which they did in the boat. At this point we are not sure if the alumina is a source of contamination in the first batch, but that potential has made us try and avoid it with the second batch. The X-ray and Meissner effect tests will help determine whether it was a necessary change.
We also performed an X-ray diffraction of the first batch (after being annealed twice) to see what possible effect that second heating had on the crystalline structure. Initial analysis of that data shows minimal change structurally. However, the pellets are showing marked improvement in the Meissner effect since the second annealing. We are not sure why at this point, and may pursue it further but time is getting scarce and we need to finalize the project as soon as possible.
We also performed an X-ray diffraction of the first batch (after being annealed twice) to see what possible effect that second heating had on the crystalline structure. Initial analysis of that data shows minimal change structurally. However, the pellets are showing marked improvement in the Meissner effect since the second annealing. We are not sure why at this point, and may pursue it further but time is getting scarce and we need to finalize the project as soon as possible.
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