Crystal Chemistry and Growth of Low Magnetic Anisotropy Crystals

摘要

A method to grow mixed cation substituted yttrium iron garnets (YIG) where the cations are calcium and silicon is described. Special flux solvent is used, based on lead oxide and is free of fluorine. Crystals of the composition (Y(3)-x-y)Ca(x)Bi(y)) (Fe2) (Fe(3-x)) O12 with x varying from 0.4 to 1.2 and y from 0.01 to 0.5 are produced. Some of the crystals could be prepared to contain Mo(6+) up to Z = 0.05. The crystals have a much lower saturation magnetization than YIG depending on the value of x. The microwave resonance absorption has a linewidth in the order of about 30 oersteds. The Curie temperature of the crystals are relatively high and even for x = 1.2 it is above 200C. Single crystals with a composition Yb3 Fe(5-x) Ga(x)O12 with x varying from 0.5 to 4.0 were grown from a PbO-PbF2 flux and the growth conditions were compared. Polycrystalline Cd Cr2S4 material was prepared by two different methods doped with Fe57. Polycrystalline Mo(6+), Ca(2+) and Si(4+) substituted YIG compounds have been prepared and the crystallographic unit cell reported. (Author)