Magnetic flux density measurements from grain boundary phase in 0.1 at% Ga-doped Nd-Fe-B sintered magnet

The magnetism of a narrow (similar to 1.6 nm) grain boundary phase produced in a 0.1 at% Ga-doped Nd-Fe-B sintered magnet was examined using electron holography. The magnetic flux density was determined to be 0.8 +/- 0.1 T, which was smaller than that for a commercial magnet free from Ga doping (similar to 1.0 T). The presence of a ferromagnetic grain boundary phase reasonably explained the functionality of the 0.1 at% Ga-doped system, such as the improvement in the squareness of the demagnetization curve. The observations provide useful information for deeper understanding of the coercivity mechanism in Ga-doped Nd-Fe-B sintered magnets. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.