Can graphene be annealed at high temperatures without damaging Zeranin wires?

  • Thread starter Thread starter Erikve
  • Start date Start date
AI Thread Summary
Graphene annealing at high temperatures (around 250°C) poses risks to Zeranin wires due to potential degradation of their coating. The experimental setup involves a pumped tube where the sample is heated, which raises concerns about damaging delicate components of the He3 cryostat. The current sample holder made of high sol cannot withstand temperatures above 120°C, prompting the use of vespel, a polymer that can handle up to 300°C. However, there is skepticism about whether the wires can survive the annealing process without burning, even with precautions like evacuating oxygen. It is suggested to consider rewiring with materials suitable for high temperatures to avoid damaging the setup.
Erikve
Messages
17
Reaction score
0
Hi all,

I have a quite easy question, but I have no experience with this. At our lab we do a lot of experiments on low temperatures (<4K). For example we use helium-3 to obtain 500mK. To obtain this temperature we use Zeranin-wires in our setup. But now our sample (graphene) should be annealed on high temperature (~250 C) before the experiment starts. The question is: will the coating on my wires burn on this temperature or is there maybe a better wire to use at top of the insert? (since only of the insert is in the oven during warming)

Thanks for your answers!
 
Engineering news on Phys.org
I think that the answer is yes, the coating will be degraded.
But I wonder why do you have to warm all your insert at that high temperature? I don't know what kind of system are you using, but He3 cryostats use to be delicated, warming them at such a temperature could damage it permanetly. For example the cryopump, the He3 valves or even the pressure inside the He3 volumen could be too high and explode.
If you can explain a bit more of your idea...
hope this helps
 
Maybe I was indeed a bit short about the details. Our experimental setup is in principle apart from the HE3-system, we can insert it in the He3-cryostat. So during the heating the sample is in a pumped tube with inside an insert (at top the sample). I have over here poorly no pictures, but you can see it as follows:

---------------------------------------------------------------------------|
--
--(stick)+++++++++++++++++++++++++++++++++++++++++===| (Sample)|
--
---------------------------------------------------------------------------|

So you pump inside and flush 3 to 4 times with helium to get rid of air and oxygen. Maybe the last part is most important to prevent burning of the wires.

But why heating my sample-holder? My sample is made of graphene, a single layer of graphite. Due to different effects the sample can be doped, more electrons or holes are on the surface of the sample. By heating and pumping on my tube, I can get rid of these charges and make the sample "neutral charged". (we can shift the so-called charge neutrality point (CNP))

So far I have used a top sample-holder made of high sol, but this melts above 120 C. This temperature is not enough too anneal fast (I have now a heavily doped sample and already annealing for 3 weeks). So the new top-part is made of vespel, a high quality polymer that melts around 300 C. But as I remember from the past it can be risky too warm up the coating of my wires.

Maybe best idea is too try this by trial and error with some test wires.
 
Well at least, you won't break your insert :). But I think that your wires will be completely cooked, even if you evacuate the oxygen the coating will be burnt, at least it happened to me with manganine wires trying to do something similar.
I advice to try to rewire the sample holder, with something better for this high temperature, but I guess that it won't be valid for a He3 cryostat. Anyway why you don't anneal the substrate and the you glue it into a sample holder?
hope this help.
 
I don't do the last step, because it will be recharged by water after removing it from he-atmosphere. So that's not an option.

I think I have to rewire the part that is in oven.
 
While I was rolling out a shielded cable, a though came to my mind - what happens to the current flow in the cable if there came a short between the wire and the shield in both ends of the cable? For simplicity, lets assume a 1-wire copper wire wrapped in an aluminum shield. The wire and the shield has the same cross section area. There are insulating material between them, and in both ends there is a short between them. My first thought, the total resistance of the cable would be reduced...
Hi all I have some confusion about piezoelectrical sensors combination. If i have three acoustic piezoelectrical sensors (with same receive sensitivity in dB ref V/1uPa) placed at specific distance, these sensors receive acoustic signal from a sound source placed at far field distance (Plane Wave) and from broadside. I receive output of these sensors through individual preamplifiers, add them through hardware like summer circuit adder or in software after digitization and in this way got an...
I am not an electrical engineering student, but a lowly apprentice electrician. I learn both on the job and also take classes for my apprenticeship. I recently wired my first transformer and I understand that the neutral and ground are bonded together in the transformer or in the service. What I don't understand is, if the neutral is a current carrying conductor, which is then bonded to the ground conductor, why does current only flow back to its source and not on the ground path...
Back
Top