Akademik Veri Yönetim Sistemi
JOURNAL OF PHYSICS-CONDENSED MATTER, cilt.16, sa.28, ss.4955-4962, 2004 (SCI-Expanded)
X-ray powder diffraction, AC susceptibility and differential scanning calorimetry (DSC) studies were performed on the polycrystalline PrMn2Ge2-xSix (0 less than or equal to x less than or equal to 2) compounds. All compounds investigated crystallize in the body-centred tetragonal ThCr2Si2-type structure with the space group I4/mmm. Substitution of Si for Ge leads to a linear decrease of the lattice constants and the unit cell volume. The lattice constants and the unit cell volume obey Vegard's law. Samples in this alloy system exhibit a crossover from ferromagnetic ordering for PrMn2Ge2 to antiferromagnetic ordering for PrMn2Si2 as a function of Si concentration x. At low temperatures, the Pr sublattice also orders for x less than or equal to 0.4. The samples with x less than or equal to 1.3 are ferromagnetic and have spin reorientation temperatures just below the Curie temperature. In the cases of x = 1.2 and 1.3, re-entrant ferromagnetism is observed. The samples with x greater than or equal to 1.6 are antiferromagnetic below the Neel temperature T-N (Mn). By comparing our results to earlier neutron diffraction and Mossbauer studies, the x-T magnetic phase diagram has been constructed.