Superconductors and graphene

This topic was created by Conundrum1885 .

  1. Conundrum1885 Bronze badge

    Superconductors and graphene

    Hi, found this on phys.org

    https://phys.org/news/2020-03-transistor-graphene-two-dimensional-superconductor.html

    As I now have the means to make a "window" material with an apparent Tc in the 278K range though not fully superconducting it does have a sharp resistance drop of over 10:1 down to below the minimum range on my DMM at the time.

    Now thanks to some nice folks in the former USSR I have some pure metal samples with known properties, I can get the exact formula with better measuring equipment but it looks like its four metals with a dopant formed using a HEA method based on slowly decreasing temperature under DC bias from an inert electrode such as Ta or W on the vertical axis. Ultrasonic standing wave may help but trying to make this as simple as possible for mass replication once I iron out all the bugs.

    To simplify things I may write some Arduino code that performs the correct procedure automatically.

    Mostly bismuth with a little zinc, tin and larger amount of indium but having problems getting exact readings due to microscale failure: before it did break a few years back I got the exact formula which is written down in my experimental notes.

    The trick as I now know is using zinc chloride flux to reduce oxygen infiltration.

    What is *really* strange is that I was able to detect signs of magnetic field spikes from a previously non magnetic material at the "critical" temperature using my EPE magnetic probe with the floppy disk drive 4 pin sensor. Dopant *might* be one of the alkali metals which would make sense (Li, Mg, K etc)

    I also noticed very similar spikes when experimenting with graphene and solvent later found to contain mostly MEK and acetone (!) but this one was completely unexplainable however Li or Pb in the matrix could in retrospect have been responsible.

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