Electron doping effect on structural and magnetic phase transitions in Sr2-xNdxFeMoO6 double perovskites

Artikel i vetenskaplig tidskrift, 2006

Polycrystalline Sr2−xNdxFeMoO6 (x=0.0, 0.1, 0.2, 0.4) materials have been synthesized by a citrate co-precipitation method and studied by neutron powder diffraction (NPD) and magnetization measurements. Rietveld analysis of the temperature-dependent NPD data shows that the compounds (x=0.0, 0.1, 0.2) crystallize in the tetragonal symmetry in the range 10–400 K and converts to cubic symmetry above 450 K. The unit cell volume increases with increasing Nd3+ concentration, which is an electronic effect in order to change the valence state of the B-site cations. Antisite defects at the Fe–Mo sublattice increases with the Nd3+ doping. The Curie temperature was increased from 430 K for x=0 to 443 K for x=0.4. The magnetic moment of the Fe-site decreases while the Mo-site moment increases with electron doping. The antiferromagnetic arrangement causes the system to show a net ferrimagnetic moment.