Three-Dimensional Self-Assembly of Core/Shell-Like Nanostructures for High-Performance Nanocomposite Permanent Magnets

Core/shell nanostructures are fascinating for many advanced applications including strong permanent magnets, magnetic recording, and biotechnology: They are generally achieved via Chemical approaches; but these techniques-limit them to nanoparticles. Here, we describe a three-dimensional (3D) self-assembly of core/shell-like nano composite magnets, with hard-magnetic Nd2Fe14B core of similar to 45 bra and soft-magnetic alpha-Fe Shell, of similar to 13 nm, through a physical route. The resulting Nd2Fe14B/alpha-Fe core/shell-like nanostructure allows both large remanent magnetization and high coercivity, leading to a record-high energy product of 25 MGOe which reaches the theoretical limit for isotropic Nd2Fe14B/alpha-Fe nanocomposite magnets. Our approach is based on a sequential growth-of the core and shell,nanocrystals in an, alloy melt. These results make an important step toward fabricating core/shell-like nanostructure in 3D materials.