Actual Trends in the Application of Rare-Earth Metals and Their Compounds in the Production of Magnetic and Luminescent Materials: A Review

Current trends in the application of rare-earth metals (REMs) in two major scientific and technological fields-the production of magnetic and luminescent materials-are considered. It is shown that it is REMs that endow these products with unique properties. The information on the content of the matrix and doping components and their influence on achieving the required characteristics of the most popular magnetic materials is systematized. The potential of new combinations of REMs for further progress in the production of magnetic materials for various purposes is described. Along with the traditional cobalt-samarium and neodymium-iron-boron compositions, new magnetic materials with increased hysteresis properties and better time-temperature stability are developed, and phases with variable valence, used as memory elements in information systems, are synthesized. In addition, the article also reviews and summarizes the results of studies in the creation of luminescent materials, which is another important area of application of REMs. Phosphors based on compounds of REMs are used in the production of high-pressure mercury lamps with improved characteristics, X-ray screens, high- and low-pressure fluorescent lamps, and screens for electrooptical converters. Narrow-band phosphors based on REM compounds are of interest for lamps used for growing plants, especially in areas with a cold climate, where growing plants year-round is possible only with the use of additional radiation sources. The trends in the synthesis of luminescent materials with varied REMs and their combinations are revealed. Emphasis is placed on the need to use chemically pure REM precursors in the synthesis of such materials. The prospects for the creation of nanophosphors, as well as the improvement of methods of synthesis and diagnostic techniques, are noted.