Fe-57 Mossbauer Spectroscopy Studies Of Sr2fe1-Xcrxmo1-Xwxo6 Double Perovskite Compounds

Polycrystalline double perovskites Sr2Fe1-x Cr (x) Mo1-x W (x) O-6 with x = 0, 0.05, 0.10, 0.15, 0.20, and 0.30 have been prepared by sold state reactions. A continuous decrease of the tetragonal unit cell parameters alpha and c with increasing x values is observed. The highest Curie temperature T (C) = 426 K is recorded for the x = 0.10 compound. Fe-57 Mossbauer spectroscopy measurements indicate a non-integral electronic configuration of similar to 3d(5.3) for the Fe ions at the ordered double perovskite structure for x <= 0.20, which reaches similar to 3d(5.4) for x = 0.30. Fe-Mo/W anti-site and anti-phase boundary defects are observed in all samples in equal concentrations of around 3% of the total number of Fe ions in their structure.