以无机盐为前驱体, 利用溶胶?凝胶法固溶合成了(1-x)Pb(Fe2/3W1/3)O3-xPb(Mg1/2W1/2)O3多铁性固溶体. XRD分析表明, 在0≤x≤1.0的掺杂范围内, 700℃煅烧所得产物都具有钙钛矿结构; x=0时得到的纯Pb(Fe2/3W1/3)O3为长程无序结构, x=1.0时可获得完全有序的纯Pb(Mg1/2W1/2)O3相, 其单胞为Pb(Fe2/3W1/3)O3单胞的2倍; 当0<x<1.0时, (1-x)Pb(Fe2/3W1/3)O3-xPb(Mg1/2W1/2)O3固溶体也为有序结构, 出现1/2 (111)及1/2 (311) XRD衍射峰, 且强度随掺杂系数x的升高逐渐增大. TEM分析证实, 煅烧产物为具有钙钛矿结构的单相固溶体, 而非两相复合物; 固溶相形貌以立方颗粒为主, 随掺杂量增加其晶胞常数线性增大, 而晶粒尺寸先减小后变大. 性能测试发现, 固溶相的磁学性能随x的增加而逐渐下降, 起因于抗磁性的Pb(Mg1/2W1/2)O3破坏了Pb(Fe2/3W1/3)O3原有的价键结构所致.
Pb(Fe2/3W1/3)O3 was modified by doping Pb(Mg1/2W1/2)O3 with Sol-Gel method using inorganic salts as precursors. At calcination temperature of 700℃, the resulted solid solution (1-x)Pb(Fe2/3W1/3)O3-xPb(Mg1/2W1/2)O3 kept a perovskite structure in the whole doping range of 0≤x≤1. The obtained Pb(Mg1/2W1/2)O3 (x=1) is fully ordered with a unit cell as two times as that of Pb(Fe2/3W1/3)O3 (x=0). Solid solution (1-x)Pb(Fe2/3W1/3)O3- xPb(Mg1/2W1/2)O3 (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)O3-xPb(Mg1/2W1/2)O3 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)O3 could destroy the -Fe3+-W-O-W-Fe3+- and -Fe3+-O-Fe3+- magnetic bonds in antiferromagnetic Pb(Fe2/3W1/3)O3 phase.
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