Lisa's Lab Notes

Where's the transition?

Here is the LCMO 30% data. The green is old high T data showing a nice sharp step. The red is the new high T data, showing no such step (and also a static offset -- the purple is the same data shifted up by .001).Where's the transition?!? Well, there still might be one, but if there is, it is very broad and not as sharp and exciting as we had hoped. A broad transition would be consistent with Kumar's data, which suggested a continuous transition from 350-550 K or so. The new data is steeper than an 860 K Debye curve, which might suggest a broad transition.

Also, I just noticed that the green data above 450K has a very similar slope but is shifted upward and with a bit more scatter. I wonder is there is something wrong with that data that shifted it up.

Things to check:

1. The old high T data (mag23) has a 'bump" in the low-r region. Where does it come from? Can it be removed (the ks data looks like there is a glitch on top of one of the peaks, CAREFULLY check glitches)? Does de-glitching change the results?
2. Why does the new data have a static shift? Try fitting with slightly different S0^2.
3. Fit all data with new cubic standards, see if results change. Try changing FT range.
   
4. Fit further neighbors to get a better fit on the high-r side of the first peak.

posted by Lisa @ 5:36 PM