Visible to the public Magnetic Domain Structures and Magnetic Properties of Lightly Nd-Doped Sm–Co Magnets With High Squareness and High Heat Resistance

TitleMagnetic Domain Structures and Magnetic Properties of Lightly Nd-Doped Sm–Co Magnets With High Squareness and High Heat Resistance
Publication TypeJournal Article
Year of Publication2019
AuthorsMachida, H., Fujiwara, T., Fujimoto, C., Kanamori, Y., Tanaka, J., Takezawa, M.
JournalIEEE Transactions on Magnetics
Date Publishedfeb
Keywordscell structure, cobalt alloys, coercive force, compositionality, cyber physical systems, grain boundaries, high heat resistance, homogenization, Internet of Things, intrinsic coercivity, irreversible demagnetization, Kerr effect microscope, Kerr effect microscopy, Kerr magneto-optical effect, lightly Nd-doped Sm-Co magnets, magnetic domain structures, magnetic domain walls, Magnetic domains, Magnetic flux, magnetic hysteresis, magnetic properties, Magnetic Remanence, magnetic resonance imaging, Magnetic separation, microstructures, neodymium, Perpendicular magnetic anisotropy, pubcrawl, remanence, remanent magnetic flux density, Resiliency, reverse magnetic domains, samarium alloys, scanning transmission electron microscopy, scanning-transmission electron microscopy, sintering, slow cooling, Sm-Co:Nd, solution treatment, spontaneous magnetisation, squareness, temperature 150.0 degC, temperature 25.0 degC, temperature coefficients
AbstractThe relationship between magnetic domain structures and magnetic properties of Nd-doped Sm(Fe, Cu, Zr, Co)7.5 was investigated. In the preparation process, slow cooling between sintering and solution treatment was employed to promote homogenization of microstructures. The developed magnet achieved a maximum energy product, [BH]m, of 33.8 MGOe and coercivity, Hcb, of 11.2 kOe at 25 °C, respectively. Moreover, B-H line at 150 °C was linear, which means that irreversible demagnetization does not occur even at 150 °C. Temperature coefficients of remanent magnetic flux density, Br, and intrinsic coercivity, Hcj, were 0.035%/K and 0.24%/K, respectively, as usual the conventional Sm-Co magnet. Magnetic domain structures were observed with a Kerr effect microscope with a magnetic field applied from 0 to -20 kOe, and then reverse magnetic domains were generated evenly from grain boundaries. Microstructures referred to as “cell structures” were observed with a scanning transmission electron microscope. Fe and Cu were separated to 2-17 and 1-5 phases, respectively. Moreover, without producing impurity phases, Nd showed the same composition behavior with Sm in a cell structure.
Citation Keymachida_magnetic_2019