Structural Ordering and Magnetic Property of Complex Perovskite Solid Solution (1-x)Pb(Fe2/3W1/3)O3-xPb(Mg1/2W1/2)O3

Pb(Fe2/3W1/3)O-3 was modified by doping Pb(Mg1/2W1/2)O-3 with Sol-Gel method using inorganic salts as precursors. At calcination temperature of 700 degrees C, the resulted solid solution (1-x)Pb(Fe2/3W1/3)O-3-xPb(Mg1/2W1/2)O-3 kept a perovskite structure in the whole doping range of 0 <= x <= 1. The obtained Pb(Mg1/2W1/2)O-3 (x=1) fully ordered with a unit cell as two times as that of Pb(Fe2/3W1/3)O-3 (x=0). Solid solution (1-x)Pb(Fe2/3W1/3)O-3-xPb(Mg1/3W1/2)O-3 (0 < x < 1.0) also has an ordered crystal structure showing supperlattice peaks of 1/2 (111) and 1/2 (311) in X-ray diffraction, whose intensities become stronger as x increases. Combining electron diffraction and elemental analysis in transmission electron microscope, solid solution (1-x)Pb(Fe2/3W1/3)O-3-xPb(Mg1/2W1/2)O-3 is verified as a single phase with perovskite structure, rather than a mixture of two phases. The particles of solid solution have a cubic morphology, and their grain size first decreases and then increases when doping coefficient x varies from 0.2 to 0.8. Due to the substitution of larger Mg2+ for smaller Fe3+ ions, its lattice constant increases linearly with the enhancement of x. According to the measured M-H curves, the magnetic performance of the solid solution decays as the doping coefficient x increases, because the formation of diamagnetic Pb(Mg1/2W1/2)O-3 could destroy the -Fe3+-W-O-W-Fe3+ - and Fe3+-O-Fe3+ - magnetic bonds in antiferromagnetic Pb(Fe2/3W1/3)O-3 phase.