Colossal magnetoresistance and Mossbauer studies of the manganites La1-xSnxMn0.985Fe0.015O3+delta

Colosssal magnetoresistance (CMR), Mossbauer spectra, and phase composition s of the iron-doped manganites, La1-xSnxMn0.985Fe0.015O3 + delta (x = 0.3 a nd 0.5), have been studied. A small amount of iron doping modifies the CMR and other magnetic properties of the manganites. La0.7Sn0.3Mn0.985Fe0.15O3 + delta exhibits CMR; the magnetoresistance coefficient with H = 20 kOe and T = 225 K is about 80%. La0.7Sn0.3Mn0.985Fe0.015O3 + delta consists of two phases, (LaSn2+)MnO3, or ABO(3), and (LaSn4+)(2)Mn2O7, or A(2)B(2)O(7). Th e ABO(3) phase has a transition from paramagnetism to ferromagnetism at T = 225 K. The CMR has its origin in the ABO(3) phase. (C) 1998 American Insti tute of Physics.