I have very fine metallic powder. I tried to do measurement by enclosing sample in the copper foil, but at a slightly high field the signals become noisy. Then next I mixed a small amount of powder in the Zircar cement, the data become noisy at the slightly higher field this time. Measurements are supposed to be performed till 600 K and I cannot apply pressure or heat the samples. Any other suggestions?
System used: Quantum Design Magnetic Property Measurement System (MPMS)
I assume you are using the oven insert for your MPMS. We usually use fine quartz tubes to hold the powder. The bottom of the tube is sealed (with a flame) and we fill the bottom of the tube to a height of perhaps 6mm. If your sample isn't very magnetic, you can do an empty sample holder measurement (take the measurement of every point in the scan) and subtract the background offline to get your signal. When you say the data is noisy, does this mean that your signal is approaching the noise level of the measurement? Or does some new noise appear? With the dc transport, you should be able to measure a 10^-5 emu signal with reasonable SNR.
If you should have any pellet pressing equipment available, it might be preferable to press your powder into a suitable size pellet (under vacuum is even better - no air bubbles). Such a pellet lets to handle itself very much as a single crystal (just no preferred orientations)...
I am performing measurement with the step size of 100 Oe between -2000 to 2000 Oe and, 500 Oe between 2000-20000 Oe. The measurement in first range is always good, when it gets into second range the data starts to deviate randomly with a jump of 0.01 emu or greater (magnetization at 2000 Oe is 0.004 emu). When the loops return back below 2000 range it again becomes smooth. Same thing happens in the negative field.
The samples are mixed with Zircar cement attached to the holder using cement. The sample portion is then wrapped with Cu foil.
Can you please explain how to seal the sample in a quartz tube. My sample properties will change if the sample is heated.
I even pressed powder into the pellet, which, holds itself quite well still I get the same problem when magnetic field crosses 3000 Oe.
Could you make any measurement ??? You can try with quartz puddle provided by quantum design. You can fix your sample by placing it on a copper tape and then wrap it on a quartz puddle. Hope this helps but not very sure.
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