Effects of Annealing on the Physical Properties of Bi2Sr2CaCu2O8+∂

We present the measured resistivity, Hall coefficient, and magnetization for three kinds of Bi2Sr2CaCu2O8+∂ ceramics subjected to various heat treatments. The Hall effect shows that in this system the carriers have hole-like characteristics. The hole density varies according to the heat treatment; the hole density increases and Tc decreases as a result of oxidation. In spite of the atmosphere in which heat treatments were performed, the flux pinning density is increased by quenching. The Hall mobility is independent of the heat treatment of Bi2Sr2CaCu2O8+∂. This result indicates that oxygen atoms enter and leave sites on planes other than the CuO2 planes in Bi2Sr2CaCu2O8+∂.