Single crystal growth and characterization of La2-xSrxCuO4 with Mn doping

A series of La1.85Sr0.15Cu1-yMnyO4(0⩽y⩽0.05) single crystal samples have for the first time been grown by the travelling-solvent floating-zone method. Instead of preheating the feed rod materials at intermediate temperatures, we directly preheat the starting materials at 1150 °C. After that we grow Mn doped samples at 0.33 mm/h, which is much slower than the widely adopted 1 mm/h rate used in the single crystal growth of La2-xSrxCuO4 samples. We believe that these improvements are crucial for obtaining Mn substitution into La2-xSrxCuO4 without inducing impurity phases. The results of magnetic susceptibility measurements indicate that the onset superconducting transition temperature of Mn doped samples (0⩽y⩽0.025) does not decrease rapidly, indicating that Mn doping is quite peculiar compared to other elemental doping cases.