高温超导体RBa_2Cu_3O_y超导转变热力学

Thermodynamics of the Superconducting Phase Transition on High T_c Superconductor RBa_2 Cu_3O_y

研究了稀土氧化物高温超导体ＲＢａ_２Ｃｕ_３Ｏ_ｙ（Ｒ：一般为稀土元素）超导转变的相变性质，认为在没有外界磁场作用时超导转变为二级相变，有外界磁场作用时为一级相变。推导出超导体ＲＢａ_２Ｃｕ_３Ｏ_ｙ在超导转变时体系的Ｇｉｂｂｓ自由能关系式。

The property of superconducting phase transition of the high T_c superconductor RBa_2Cu_3O_y (R: most rare earth elements) was investigated. The conclusion was drawn that the phase transition changed from first order in magnetic field to second order in non-magnetic field. The representation of the Gibbs free energy of the superconductor RBa_2Cu_3O_y at the superconducting-normla state transition in non-magnetic field was derived.