This paper presents an up-to-date magnetic materialinvestigation and overview on magnetic materials used in rotatingelectrical machines. The focus is on small to medium-sizedhigh-performance and high-efficiency permanent-magnet andinduction motors for different application scenarios. The inves-tigated materials include silicon-iron, nickel-iron, and cobalt-iron lamination steels, as well as soft magnetic composites andamorphous magnetic materials. The technical focus is on themagnetic properties and iron losses as well as the manufacturinginfluence and required thermal treatments during the manufac-turing process. A new loss to flux density factor is introducedto compare theBHmagnetization curve and the iron losses ofdifferent materials in the same diagram. The aim of the paper isto give the machine designer an efficient material overview andselection guide during the early machine design process.