Superconductivities of n-type Nd1.85Ce0.15CuO4 - y prepared under high pressure

In this work we provide the report on the preparation of a bulk n-type NdCeCuO superconductor using a high-pressure high-temperature sintering procedure. The superconductor was obtained by sintering as-prepared material at 4.0 GPa at 530 °C for 20 min and required no additional reducing treating. The sample shows a higher onset temperature T_con (32 K), a higher zero resistance temperature T_c0 (22 K), and a much lower resistivity than a standard bulk sample. Indeed the room-temperature resistivity and the quasimetallic resistivity in the normal state for our polycrystalline sample are similar to those of single crystals. This high-pressure sintering procedure reduces weak link effects and opens the possibility of preparing high-quality bulk n-type superconductors.