Study of Fe-doped La1-xCaxMnO3 (x similar or equal to 1/3) using Mossbauerspectroscopy and neutron diffraction

La2/3Ca1/3MnO3 doped with Fe were studied by Mossbauer spectroscopy and neu tron powder diffraction. The Mossbauer spectra (MS) reveal that Fe substitu tes for Mn as Fe3+ (S= 5/2) and is antiferromagnetically coupled to the Mn host lattice. The magnetic behavior, from the neutron diffraction data, is that of atypical 3D Heisenberg ferromagnet. The temperature evolution of th e MS differs from that of the neutron data, especially above 40 K. The data can be interpreted using a model based on an antiferromagnetic impurity in a ferromagnetic host. In such a system, the ground state is inhomogeneous resulting in spin states with reduced spin and the spin excitations are loc alized in the immediate neighborhood of the impurity atoms. Finally, at T a pproximate to 0.9T(c) the MS indicate the onset of charge localization. [S0 163-1829(99)09101-8].