Synthesis of mesoscopic particles of multi-component rare earth permanent magnet compounds

Abstract

Multielement rare earth (R)–transition metal (T) intermetallics are arguably the next generation of high-performance permanent magnetic materials for future applications in energy-saving and renewable energy technologies. Pseudobinary Sm 2 Fe 17 N 3 and (R,Zr)(Fe,Co,Ti) 12 (R = Nd, Sm) compounds have the highest potential to meet current demands for rare-earth-element-lean permanent magnets (PMs) with ultra-large energy product and operating temperatures up to 200°C. However, the synthesis of these materials, especially in the mesoscopic scale for maximizing the maximum energy product ( ), remains a great challenge. Nonequilibrium processes are apparently used to overcome the phase-stabilization challenge in preparing the R–T intermetallics but have limited control of the material’s microstructure. More radical bottom-up nanoparticle approaches based on chemical synthesis have also been explored, owing to their potential to achieve the desired composition, structure, size, and shape. While a great achievement has been made for the Sm 2 Fe 17 N 3 , progress in the synthesis of (R,Zr)(Fe,Co,Ti) 12 magnetic mesoscopic particles (MMPs) and R–T/T exchange-coupled nanocomposites (NCMs) with substantial coercivity ( ) and remanence ( , respectively, remains marginal.

A route to carbon-sp3 bridging spiro-molecules: synthetic methods and optoelectronic applications

“…[1][2][3][4] This includes rare earth permanent magnets, semiconductors, luminescent materials, ecological environments, energy, catalytic materials and technologies, and biomedical applications. [5][6][7][8][9][10][11][12][13][14][15] Among functional materials with different properties, organic functional materials have gained significant attention due to their abundant raw material sources, low cost, adjustable properties, light weight, flexibility, stretchability, tunable spectra, and the ability for largearea fabrication. 16,17 They have emerged as the most promising…”