Private: Neutron Diffraction of MnO
Procedure
- Report to the Centre for Crystal Growth, ABB 435, to meet with Dr. Qiang Chen. He will give you an aluminum sample can and direct you in loading the power MnO sample into the can and sealing it. You should be loading 5-10 grams of MnO into your sample can. Please weigh and record the weight of your sample before you load it into the can. After loading the sample powder into the can, mark the sample height on the outside of the can and take a picture of it with your phone (so you have a record of how you loaded the sample).
- You will meet either Prof. Gaulin or Dr. Bo Yuan at ABB 238, and one of them will access you into the McMaster Nuclear Reactor and take you to Beamport 6. This step may or may not happen directly after the sample preparation.
- You will assist Dr. Bo Yuan in attaching the loaded sample can into a closed cycle refrigerator. Once attached, you will assist Dr. Yuan in sealing the refrigerator, and placing it in its proper position on the sample table of the MAD diffractometer. You will then start pumping down the refrigerator so that the sample can is in a good enough vacuum to cool down to low temperatures. When the vacuum is low enough (ask Dr. Yuan) you can turn on the compressor for the closed cycle refrigerator and start cooling the sample.
- Once the sample is loaded in the incident neutron beam, you can start the C2 detector counting and take several data sets, perhaps 5 minutes each, to see what your signal looks like.
- Armed with the information of how long it takes to get a useful neutron diffraction pattern on your sample, you can begin to take the data that you will analyze. You should aim to take at least 5 different temperature data sets between 5 K and 200 K. The magnetic phase transition is near 120 K, so you should choose the temperatures appropriately, such that you can see the changes in the neutron diffraction pattern from the low temperature regime, where signatures of Antiferromagnetism are clear, to high temperatures, where your MnO sample is a Paramagnet.