Magnetic relaxation measurement of the infinite-layer superconductor Sr0.9La0.1CuO2

The relaxation of the irreversible magnetization in the superconducting state for the grain-aligned electron-doped infinite-layer superconductor Sr0.9La0.1CuO2 was measured. The normalized flux creep rate, S(T), and the current-dependent activation barrier, U(j), were obtained. Based on S(T) and U(j), three different magnetic relaxation behaviors were observed in the superconducting state, and this is quite different from what is seen in the highly anisotropic cuprate superconductors. Even compared to the absolute value of S(T) for the most isotropic superconductor YBa2Cu3O7-δ among the cuprate superconductors, the absolute value of S(T) for Sr0.9La0.1CuO2 is quite small. Along with the recent observation of a striking s-wave gap symmetry and the absence of any significant spin fluctuation in this electron-doped cuprate, which is quite different from the behavior seen in hole-doped cuprates, the magnetic properties of Sr0.9La0.1CuO2 are not very similar to those of the hole-doped cuprates. U(j) has a H-α form with α ∼0.2. This value is quite different from the predictions of the Yeshurun and Malozemoff model and the Tinkham model where α=1