R-Fe-B BASED THIN FILM MAGNET AND METHOD FOR PREPARATION THEREOF

摘要

An R-Fe-B based thin film magnet which comprises an R-Fe-B based alloy containing 28 to 45 mass % of an R element (wherein R represents one or more of rare earth lanthanide elements) and is formed into a film by a physical means, wherein the alloy has a composite structure comprising R2Fe14B crystals having a crystal diameter of 0.5 to 30 mum and grain boundary phases being present at borders of said crystals and being rich in the R element; and a method for preparing the R-Fe-B based thin film magnet, which comprises heating the film to a temperature of 700 to 1200°C during the above physical film forming and/or in the subsequent heat treatment, to thereby grow crystal grains and form grain boundary phases being rich in the R element. The above R-Fe-B based thin film magnet exhibits improved magnetization characteristics.