>>891913Here's the procedure I've been referring to:
Note: Avoid the use of metal spatuals in this experiment; metal impurities will reduce the superconducting properties of the product. The reactants used are mildly toxic, so avoid contact and inhalation of dusts.
weigh out 225.8 mg (1 mmol) of Y2O3 (yttrium oxide), 789.4 mg (4 mmol) of BaCO3 (barium carbonate), and 477.4 mg (6 mmol) of CuO (Copper(I) oxide). Try to get each within 0.1 mg. In a fume hood, combine the powders in a mortar and mix them with a pestle until thoroughly mixed (at least 15 min). The final powder should be grey with no lumps. Transfer the powder to a platinum or alumina crucible and place it inside the center of the fused silica tube running through a temperature controlled furnace, and position the furnace's thermocouple as near to the crucible as possible. Connect one end of the tube to a regulated oxygen cylinder, and the other end to a bubbler. Regulate the flow through the tube to 1-2 bubbles per second. Heat the furnace to 970 degrees C for 2-3 hours. With oxygen still flowing, turn the furnace off and allow it to cool. When it reaches 700 C, the furnace can be opened to accelerate cooling. Once the temperature drops below 200 C, the oxygen tank can be disconnected. Remove the tube when it is cool enough to handle. The product should be black, and the particles should be sintered together. Grind the sample into a fine powder. From here it can be pressed into pellets which allows the meissner effect to be displayed.
