Microstructure and magnetic properties of Sm2(Fe, Si)17Cx α-Fe nanocomposite magnets prepared under high pressure

We present microstructure and magnetic properties of Sm-2(Fe, Si)(17)C-x/alpha-Fe nanocomposite magnets prepared under a pressure of 4 GPa at a temperature of 923 K. A high-pressure experiment was carried out in a belt-type pressure apparatus. Analyses of x-ray diffraction and transmission electron microscopy show that the nanocomposite magnets have a grain size of 6-8 nm, which provides a strong exchange coupling between hard and soft magnetic phases. As a result, the magnets have, compared with nanocomposite magnets prepared under normal pressure, a significant increase in both coercivity, from 132 to 500 kA/m, and remanent magnetization, from 0.68 to 0.83M(s). (C) 1999 American Institute of Physics. [S0003-6951(99)04104-2].