Modern Applications of Magnetic Materials: Trends and Challenges

The paper provides an overview of the development of advanced magnetic materials studied by the author and colleagues. The review covers the early history and advanced medical applications of the giant magnetocaloric effect (MCE) in magnetic materials with first-order phase transitions. Unlike the MCE, which has known limiting specific values at about 18 K/T, the limiting spatial dimensions of electrically large antennas and methods to reduce them have not yet been established, nor have the limiting values for the power density of permanent magnet synchronous motors (PMSMs). The work discusses potential applications of hybrid and textured materials that simultaneously exhibit high magnetic, dielectric, and conductive properties for electromagnetic (EM) wave compression, enabling the downsizing of the electrically large antennas by orders of magnitude. Estimates suggest that the power density limit of PMSMs could reach approximately 1 MW/L, which is at least an order of magnitude higher than the current level of mass-produced PMSMs. The paper also proposes potential future applications of soft magnetic materials with magnetic phase transitions in controllable-salient PMSMs , marking an initial consideration of a smart rotor where the direction of magnetic flux can be adjusted by temperature. For the first time, the term “multi-reluctance materials” was introduced, characterizing magnetic materials with a change in the value of magnetic resistance under the influence of temperature, stress and/or magnetic or electric fields. Importantly, both the antenna and the smart rotor concept aim to achieve the same goal: modifying the properties of the electromagnetic space around the sources of electromagnetic fields. Recent advancements in balancing high magnetic properties of permanent magnets with cost and supply chain risks are also discussed.