101 three sixty five

Super conductor demonstrating the Meissner magnetic levitation effect:

A samarium-cobalt magnet floats above a handmade disk of YBa_^₂Cu_^₃O_{^_7.X}, a high temperature ceramic superconductor.
These are easy to make providing you have access to the chemicals, a muffle furnace and a press of some sort:

Obtain some yttrium oxide, barium carbonate and copper oxide.

The pellets weigh about two grams each. Mix them in the proportion of one mole of yttrium to two moles of barium to three moles of copper.

Grind the solids togeter in a mortar and pestle until you have a fine powder.

Put the powder into a crucible and cook it for four hours between 900°C and 1000°C.

Take the mixture out of the furnace and grind it back into a fine powder.

Put the powder into a press or pile it into the center of a brass washer about a millimeter thick.

If you use a washer, set it on a piece of copper sheet, and put another piece of copper on top of it.

Whack it hard and square with a hammer once.

Slide the washer onto a ceramic planchette, that is, a small tile.

Carefully remove the copper and the washer from the disk. If the disk falls apart, try again with a bit more powder.

Put the panchette into a 'muffle' furnace and heat the disks quickly as close to 1000°C as you can get, but do not exceed this temperature.

Cook the disk for 24 hours or so with the furnace's door open so that air can circulate freely.

Slowly reduce the temperature of the furnace to room temperature over six hours or so.

The disk is now ready to use. Put the disk on the bottom of a styrofoam cup and poured a amall bit of liquid nitrogen onto it. (I get LN2 from Praxair where it's about twenty bucks a gallon.)

Carefully set a samarium cobalt (or other high gauss) magnet onto the cold disk. It should float like the one shown above.

CAUTION: Handle the chemical carefully, since they are toxic (especially barium carbonate) and prolonged contact with liquid nitrogen will cause frostbite. I probably don't need to tell you that the thousand degree muffle furnace is very hot and will burn you if you touch it, but I will.
Here are alternate instructions to make YBCO from Colorado Futuresciences.
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