Abstract
Giant strain-induced ferromagnetism (SIF) has been observed in Fe59Mn17Al24 single crystals. The crystals in either the L21 or B2 ordered state are weakly magnetic, with saturation magnetization, M s, of 9–10 emu/g. After a 60% thickness reduction, the M s of the L21 crystal increased to 89 emu/g, whereas the M s of the B2 crystal after a 53% reduction was 96 emu/g, an M s approximately four times larger than that of the largest SIF observed in other ordered alloys. By comparison, mechanically alloyed powder of the same composition, which had a fully-disordered bcc structure, showed a similar M s of ∼90 emu/g. The increased M s in strained Fe59Mn17Al24 single crystals is attributed primarily to the generation of increased magnetic coupling due to chemical disordering. This large M s is substantially reduced after annealing at 573 K.
Acknowledgements
This research was supported by National Science Foundation Grant DMR 0552380. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF or the U.S. Government.