Mossbauer studies of new CMR compounds (La1-xSnx)2(Mn0.985Fe0.015)2Oy

Mossbauer spectra of (La1-xSnx)(2)(Mn0.985Fe0.015)(2)O-y (x = 0.2, 0.3, 0.4 and 0.5) from room temperature to 4.2 K have been studied; in addition X-ray diffraction patterns at room temperature have been obtained. The results show that the phase compositions of (La1-xSnx)(2)(Mn0.985Fe0.015)(2)O-y are strongly dependent on the Sn concentrations and on the heat treatment. The manganites with a: = 0.2, 0.3 and 0.4 after annealing in air at 1200 degrees C appear to consist of two phases, ABO(3) and A(2)B(2)O(7) Their Mossbauer spectra are paramagnetic doublets at room temperature that become sextets at T similar to 230 K and similar to 60 K. The ABO(3) phase appears to be the source of the CMR in manganite (La0.7Sn0.3)(2)(Mn0.985Fe0.015)(2)O-y.