Permanent magnets

Abstract

Magnetic materials, also known as ferromagnetic materials, are those that have strong induced magnetization (i.e., induced field) M under the effect of weak externally applied magnetic fields H. At room and higher temperatures, only three elements are naturally ferromagnetic: Iron (Fe), Nickel (Ni) and Cobalt (Co) and some rare earth materials like Gadolinium (Gd) and Dysprosium (Dy). Many of the ferromagnetic alloys, including Permanent Magnets (PMs) have one or more of these elements. Permanent Magnets (PMs) are among the fastest growing materials of the past five decades. They have been the focus of intensive research to further enhance their superior characteristics. Understanding the magnetic properties of PMs is of great importance in electrical and electronic power engineering because most of the electromagnetic energy conversion in high efficiency—high performance applications use PMs (e.g., Permanent Magnet Synchronous Machines).