Method for growth of oversized crystal with the photo-magnetic function of rare earth orthoferrite

Abstract

The invention relates to a method for growth of an oversized crystal with the photo-magnetic function of rare earth orthoferrite, and belongs to the technical field of crystals with the photo-magnetic function. The preparation method comprises the following steps: taking high-purity R2O3 and Fe2O3 as raw materials; weighing Sm2O3, Tb2O3 and Fe2O3 at a molar ratio of 1:1:2, and weighing Pr6O11 and Fe2O3 at a molar ratio of 1:3; sintering the weighed materials in the air to prepare a polycrystalline charging bar; conducting pretreatment on the obtained charging bar at a high temperature close to the melting point of the charging bar, and then placing the pretreated charging bar in a floating-zone furnace for growth. The method has the characteristics that the lower end of the upper charging bar takes the shape of a reverse cone, which facilitates not only the butt joint between the upper charging bar and the lower charging bar but also diameter extension of the crystal; however, power needs to be improved and airflow needs to be adjusted during the diameter extension, so that fusion in a fusion zone can be uniform; optimum growth power can be selected for steady growth in the later period; the diameter of the prepared crystal exceeds 18 mm and breaks through a design limitation of the optical floating-zone furnace (15 mm); the prepared crystal is longer than 25 mm; the prepared oversized crystal can provide a technical basis for subsequent device applications.

Description

technical field [0001] The invention relates to a super-large rare earth orthoferrite optomagnetic functional crystal Sm grown by an optical floating zone method 0.5 Tb 0.5 FeO 3 A single crystal method belongs to the field of crystal growth. Background technique [0002] Functional materials are one of the most important leading and basic materials for the development of high-tech in the 21st century. Internationally, the development and research of new functional materials has been very active. Its progress has promoted the rapid development of cutting-edge high-tech industries such as information, electronics, machinery, chemicals, aerospace and communications. As a functional material, rare earth orthoferrite materials have great research value and application prospects due to their various functional properties. As early as 1950, Forestier et al. discovered the magnetism of orthoferrite, which was also the earliest magnetic bubble material. Until the 1960s and 1970...

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Problems solved by technology

There are many defects in the growth of RFeO3 crystals by the flux method. The flux can reduce the melting temperature, but the content of the flux is very high, and the mass fraction of the melt is generally only 10%-15%. As a result, the amount of melt crystallization is very small, and large crystal particles cannot be obtained. Not only the size of the crystal is small, but also the phase relationship is very complicated, and PbFe12O19 is easy to appear isopackage phase

In addition, the corrosion of precious metal crucibles by iron oxides is difficult to avoid, and the pollution of lead and barium oxides to the environment cannot be ignored.

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