Magnetic, electric and thermal properties of La0.7Ca0.3Mn1-xFexO3 compounds

Magnetization, resistivity and specific heat of La0.7Ca0.3Mn1-xFexO3 (0.0 less than or equal to x less than or equal to 0.12) are investigated between 77 and 300 K. The substitution of Fe for Mn does not alter the lattice constants and structural symmetry of the parent compound significantly, but results in a reduction of the magnetization, an increase of the resistivity, decreases of the magnetic and metal-insulter transition temperatures. The substitution also introduces inhomogeneities in the compounds. The experimental results indicate that Fe ions exist in the form of trivalent ions in the compounds, acting as trapping centers and thus blocking the site-percolation path of the e(g) electrons. (C) 1999 Elsevier Science B.V. All rights reserved.