We investigated the effect of processing conditions on the structure and physical properties of the polycrystalline samples of Ca0.8Fe2Se2 prepared via solid state reaction. X-ray diffraction showed that the main phas...We investigated the effect of processing conditions on the structure and physical properties of the polycrystalline samples of Ca0.8Fe2Se2 prepared via solid state reaction. X-ray diffraction showed that the main phase became FeSe when the sintering temperature increased above 350 ℃. The temperature dependence of magnetization （M-T curves） recorded in zero-field-cooled mode by SQUID magnetometer showed some bumps at around 120 K to 140 K. These bumps moved to lower temperatures when the processing temperature increased above 550 ℃. On the other hand, pure FeSe materials produced at 900 ℃ for 24 h showed a sharp superconducting transition Tconset = 8.16 K and the critical current density of 6,252 A/cm2 at 5 K, self-field. SEM results indicated an enhanced grain connectivity.展开更多
文摘We investigated the effect of processing conditions on the structure and physical properties of the polycrystalline samples of Ca0.8Fe2Se2 prepared via solid state reaction. X-ray diffraction showed that the main phase became FeSe when the sintering temperature increased above 350 ℃. The temperature dependence of magnetization （M-T curves） recorded in zero-field-cooled mode by SQUID magnetometer showed some bumps at around 120 K to 140 K. These bumps moved to lower temperatures when the processing temperature increased above 550 ℃. On the other hand, pure FeSe materials produced at 900 ℃ for 24 h showed a sharp superconducting transition Tconset = 8.16 K and the critical current density of 6,252 A/cm2 at 5 K, self-field. SEM results indicated an enhanced grain connectivity.
