Electronic homogeneity in The overdoped regime of The electron-doped high-T_c superconductors

In order to investigate The electronic homogeneity in electron-doped high-T_c cuprates, magnetization and specific heat measurements have been performed for Pr_1-xLaCe_xCuO₄ single crystals with x 0.13-0.17. It has been found from The magnetization curve that The hysteresis is relatively small and that The so-called second magnetization peak is absent for every x. Moreover, The Sommerfeld constant in The ground state has shown HlnH dependence on magnetic field H for every x, suggesting that The superconductivity is not pure but dirty. These results are in contrast to those observed in The overdoped regime of hole-doped La_2-xSr_xCuO₄ where an inhomogeneous superconducting state is formed in spite of The superconductivity being pure. Therefore, it has been concluded that a rather homogeneous electronic state is realized in The electron-doped cuprates, suggesting different electronic states between hole- and electron-doped cuprates.