Patent ID: 7790300

Claim:
An R—Fe—B alloy based thin film magnet comprising an R—Fe—B based alloy which contains 28 to 45 percent by mass of R element (where R represents at least one type of rare-earth lanthanide elements) and which is deposited on a base material by a physical film forming method into an alloy film, wherein the alloy film has a thickness is 0.2 to 400 μm, and wherein the R—Fe—B based alloy has a composite texture comprising R 2 Fe 14 B crystals grown by heat treatment of said alloy film and having a crystal grain diameter of 3 to 30 μm which is larger than a single-magnetic-domain grain diameter, wherein a plurality of magnetic domains are present in the crystal grains, and R-element-rich grain boundary phases formed by the heat treatment is present at boundaries between the crystals, and the R—Fe—B alloy has a nucleation type coercive force.