PHYSICA B-CONDENSED MATTER, cilt.349, sa.1-4, ss.384-389, 2004 (SCI-Expanded)
X-ray diffraction (XRD) and AC magnetic susceptibility measurements have been performed on polycrystalline LaMn2-xCoxSi2 (0.0 less than or equal to x less than or equal to 1.0) silicides to investigate how the ferromagnetic interactions in LaMn2Si2 are affected by Co substitution. All the compounds crystallize in the naturally layered ThCr2Si2-type structure with the space group I4/ mmm. Substitution of Co for Mn leads to a linear decrease in the lattice constants and also the unit cell volume. For the samples with x less than or equal to 0.4, a ferromagnetic ordering within the Mn sublattice occurs below the Curie temperature T-C(Mn). T-C(Mn) decreases with the cobalt content from 310 K (x = 0) to 186 K (x = 0.4). For the samples with x less than or equal to 0.3, the temperature dependence of the AC susceptibility shows a distinct feature below T-C(Mn). These samples have a mixed state composed of ferromagnetic and anti-ferromagnetic phases. The samples with x = 0.6 and have the Neel temperature associated with anti-ferromagnetic behavior. The results are collected in the partial magnetic phase diagram. (C) 2004 Elsevier B.V. All rights reserved.