The effect of flake thickness on anisotropic SmCo₅ nanoflakes/submicron-flakes with high energy product

Establishing an effective process to synthesize anisotropic magnetic nanopowders that have both high energy products and high coercivity is highly desirable for many applications. A recent effort using surfactant-assisted high energy milling is proved to be capable of making SmCo₅ nanoflakes/submicron-flakes with high performance. Using the cast alloy as a starting powder, a series of the flakes with various thicknesses were made, which had energy product values up to 22 MGOe and coercivity values up to 21 kOe. The highest coercivity corresponds to a typical flake thickness of 180 nm. The key to our technique is retaining the crystallinity, which allows a high degree of anisotropy to be produced. Results of the analyses from the micrograph of SEM, XRD patterns, and magnetic measurements demonstrate the effect of flake thickness on the magnetic properties. More importantly, a relationship of property-morphology correlation in nanoscale is established for rare earth magnetic powder/flakes.