First principles study of transition-metal substitutions in Sm–Co permanent magnets

Authors

Renat F. Sabirianov, University of Nebraska at OmahaFollow
Arti Kashyap, University of Nebraska-LincolnFollow
Ralph Skomski, University of Nebraska-LincolnFollow
Sitaram Jaswal, University of NebraskaFollow
David J. Sellmyer, University of Nebraska-LincolnFollow

Date of this Version

9-20-2004

Comments

Published by American Institute of Physics. Appl. Phys. Lett. 85, 2286-2288 (2004). ©2004 American Institute of Physics. Permission to use. http://apl.aip.org/jap/.

Abstract

The microchemistry and magnetism of conventional and high-temperature Sm–Co permanent magnets are investigated by first-principles calculations. Particular emphasis is on the site preference for the substitution of Cu, Ti, and Zr in SmCo₅ and Sm₂Co₁₇ compounds. Cu substitution is more favorable in the 1:5 phase, in agreement with experimental findings. Titanium and zirconium have positive solution energies for both the phases, with Ti(Zr) having slight preference for the 1:5 (2:17) phase. Some Zr may segregate to the phase boundaries because of its large solution energy. For Ti and Zr the dumbbell site of the 2:17 phase is preferred over the other three inequivalent cobalt sites. These results are used to discuss the observed cellular nanostructure of the high-temperature Sm–Co hard magnets with composition close to the 2:17 phase.