Preparation method of iron-based REFeAsO1-xFx superconducting material

Abstract

The invention relates to a preparation method of a iron-based REFeAsO1-xFx superconducting material, wherein RE is one of lanthanum, cerium, praseodymium, neodymium, samarium or gadolinium, when RE is lanthanum, x is more than or equal to 0.03and less than or equal to 0.02; and when RE is one of cerium, praseodymium, neodymium, samarium or gadolinium, x is more than or equal to 0.05 and less thanor equal to 0.35. The method comprises the following steps: a. according to stoichiometric ratio of the iron-based REFeAsO1-xFx superconducting material, under argon protective atmosphere, respectively weighing REAs, Fe, Fe203 and REF3 nanoparticle with particle diameter of 5-100 nano, mixing and grinding tabletings; b. under the argon protective atmosphere, packing the tablettings by using tantalum sheets and sealing the tablettings in a vacuum quartz tube; and c. putting the quartz tube in a sintering furnace, under the argon protective atmosphere, ringing temperature at 100-200 DEG C / h to 1050-1100 DEG C / h, heat preserving for 36-50 hours, and cooling with the furnace to gain the material. The method has low preparation temperature, and the prepared iron-based REFeAsO1-xFx superconducting material has high purity, determined compositions, uniformity, stable performance and high superconducting transition temperature.

Description

technical field [0001] The invention relates to an iron-based REFeAsO 1-x f x Methods for the preparation of superconducting materials. Background technique [0002] In early 2008, Japanese and Chinese scientists successively reported the discovery of a new class of high-temperature superconducting materials—iron-based superconducting materials, which aroused widespread concern in the scientific community. Japanese scientists first discovered that LaFeAs[O 1-x f x ] Compounds have superconducting properties at a critical temperature of 26 Kelvin ("Journal of the American Chemical Society" volume 130, p. 3296). Subsequently, the research team led by Chen Xianhui from the University of Science and Technology of China discovered that SmFeAsO 0.85 f 0.15 The compound also becomes a superconductor at a critical temperature of 43 Kelvin (Nature vol. 453, p. 761). Subsequently, a series of Fe-based REFeAsO 1-x f x Superconducting materials have appeared one after another. ...

AI Technical Summary

Problems solved by technology

When prepared under normal pressure, it needs to be sintered in a quartz tube, and the minimum sintering temperature needs to be 1150°C, especially GdFeAsO 1-x f x The preparation temperature of superconducting materials needs to be 1200°C. Due to the high sintering temperature, it has reached the limit temperature of the quartz tube for sintering, and the fluorine volatilized in the reaction will chemically react with the quartz tube, making the quartz tube easy to break, resulting in The actual group separation of the obtained sample deviates greatly, and the sample contains a large number of impurity phases

During high-pressure preparation, a high-pressure condition of 3-6GPa is required. It is very difficult to realize such a high-pressure condition, and the high-pressure equipment is complicated and costly.

After testing, the single-phase properties of the samples prepared by the high-pressure method are still poor

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