Papers by Author: Don Keun Lee

Abstract: The magnetic α-Fe nanoparticles were carried out using two-preparation methods that include solution phase metal salt reduction and organometallic precursor decomposition. Under the different reaction conditions such as precursor and reaction time, the magnetic properties of α-Fe nanoparticles were studied. The size of nanoparticle was confirmed by transmission electron microscope (TEM) images. The magnetic properties were characterized with saturation magnetization(Ms) from hysteresis loop by vibrating sample magnetometer (VSM). The crystallinity and structure of α-Fe nanoparticles was investigated by X-ray diffraction (XRD).

Abstract: We report the core/shell type as the interesting one of the various techniques to prepare exchange-coupled permanent magnet. In this study, the exchange-coupled Nd2Fe14B/α-Fe was prepared by high energy ball mill process and chemical reduction. Nd15Fe77B8 powder prepared by high energy ball mill process was coated with α-Fe nanoparticle by chemical reduction. α-Fe nanoparticle on the ball milled Nd15Fe77B8 was synthesized by chemical reduction with borohydride as a reducing agent in aqueous solution. After annealing, Nd2Fe14B/α-Fe forming core/shell shape has exchange-coupling effect and was identified by using XRD, FE-SEM, VSM, TMA and EDX.