Rapid preparation of YBa2Cu3O7-x with T-c similar to 90 K using a domestic microwave oven

High-T-c superconducting samples of YBa2Cu3O7-x with T-c similar to 90 K have been prepared in a short time of 25 min, using a domestic microwave oven operated at 2.45 GHz and 200 W, without any post-heat treatment. Post-heat treatment is not necessary due to improvement of the sample environment during the microwave process. That is, a pellet of mixed powders of raw materials is surrounded by mixed powders of raw materials and subsequently wrapped in glass wool, in order to suppress rapid dissipation of heat from the surface of the pellet. This leads to successful preparation of homogeneous and oxygenated samples of YBa2Cu3O7-x.