Order–disorder effects in nitrided Sm–Fe permanent magnets

Authors

B.E. Meacham, University of Utah, Salt Lake City, Utah
Jeffrey E. Shield, University of Nebraska - LincolnFollow
D.J. Branagan, Idaho National Engineering and Environmental Laboratory, Idaho Falls, Idaho

Date of this Version

5-1-2000

Comments

Published in JOURNAL OF APPLIED PHYSICS VOLUME 87, NUMBER 9. © 2000 American Institute of Physics. Used by permission.

Abstract

Rapidly solidified Sm₁₁Fe₈₉ was observed to form partially ordered Sm₂Fe₁₇. The ordering increased systematically with annealing temperature, reaching an order parameter of 0.8 after annealing at 950 °C for 15 min. The coercivity of the corresponding interstitial compound Sm₂Fe₁₇N_x varied with annealing temperature and thus order parameter. The coercivity reached a maximum for an order parameter of 0.45–5, then dramatically decreased as the order increased. This behavior is characteristic of demagnetization controlled by domain wall pinning by antiphase boundaries.