M. Tabuchi et al., ELECTROCHEMICAL AND MAGNETIC-PROPERTIES OF LITHIUM MANGANESE OXIDE SPINELS PREPARED BY OXIDATION AT LOW-TEMPERATURE OF HYDROTHERMALLY OBTAINED LIMNO2, Solid state ionics, 89(1-2), 1996, pp. 53-63
Cubic and tetragonally distorted lithium manganese oxide spinels (LiMn
O2+x) were obtained by progressive oxidation of LiMnO2 between 300 and
400 degrees C. Orthorhombic LiMnO2 was prepared by hydrothermal treat
ment of either gamma-MnOOH or Mn(COOCH3)(3) . 2H(2)O with LiOH . H2O i
n large excess. The reversible specific capacity for LiMnO was found t
o be sensitive to average manganese valency changeable by the oxidizin
g condition. The LiMnO2+x exhibits the ferromagnetic behavior with T-c
= 20-40 K and the occurrence of spontaneous magnetic moment is associ
ated with the decrease in the development of ferromagnetic interaction
accompanying the decrease in the average shortest Mn-Mn distance betw
een Mn ions on octahedral 16d sites.