New developments in samarium-based permanent magnets

Abstract

As the power density of motors continues to increase, enhancing energy efficiency has become a critical requirement. Currently, Nd-Fe-B magnets are the predominant choice for high-efficiency motor applications due to their superior magnetic properties. However, improving their thermal stability necessitates the use of heavy rare-earth elements such as dysprosium (Dy) and terbium (Tb), which are subject to significant supply constraints. These limitations have spurred growing interest in samarium-based (Sm-based) magnetic materials. Among them, Sm-Co magnets exhibit exceptional thermal stability, rendering them highly suitable for high-temperature environments. In addition, Sm-Fe magnets are anticipated to deliver superior magnetic performance in future applications. This paper presents a comprehensive review of recent research and development progress in Sm-Co and Sm-Fe magnets.