Magnetic and Electric Properties of Perovskite Manganites La_(1.2)Sr_(1.8)Mn_2O_7 Single Crystal

Single crystals of La1.2Sr1.8Mn2O7 were melt-grown in flowing air in a floating-zone optical image furnace.The quality of the single crystals was determined with x-ray diffraction and Laue diffraction.Selected high quality single chips were cut into rectangularity and their magnetic properties and transport properties were measured by SQUID four terminal method,respectively.XRD pattern indicates that the powedr is a single phase.The sample shows paramagnetic in high temperatrure.The magnetization increased rapidly at 110K and was saturated gradually with decrease of temperature.Single crystal sample has less defects than polycrystalline sample and the resistivity is very small.