Magnetic and Electrical Property in Mg~(2+) Deficient La_(1.4)Sr_(1.6)Mn_2O_7 Perovskite

摘要

The nominal compositions of La_(1.4)Sr_(1.6-x)Mg_xMn_2O_7 (x=0, 0.1, 0.2, 0.3, 0.4) have been synthesized using solid-state reaction method. The XRD analyses show that the x=0 compound is pure I4/mmm tetragonal bilayered perovskites phase, while they are mixture of an orthorhombic ABO_3-type perovskite and tetragonal bilayered perovskites for x=0.1, 0.2 and 0.3). When x is 0.4, the compound is pure orthorhombic ABO_3-type perovskite. For lightly doped samples (x=0.1 and 0.2), the Curie and Nair temperature decreases with the increasing Mg~(2+) doping, while the metal-insulation transformation temperature is 90K and 140K, respectively. For heavy doped samples (x=0.3 and 0.4), the magnetic property shows spin-glass state, and the resistance increases nearly 4 order of magnitudes.