ThMn12-type (Sm,Zr)1(Fe,Co,Ti)12 compounds show great potential for permanent magnets. Magnetically hard anisotropic powders prepared via reduction-diffusion exhibit a significant increase in coercivity from 0.45 T to 1.26 T as the processing temperature is raised from 990{\deg}C to 1220{\deg}C. Structural and microchemical analyses at high-resolution reveal that high-temperature processing annihilates grain boundaries (GBs) and reduces the density of twin boundaries (TBs), which are defects acting as weak links limiting the coercivity in the 1:12 system. Ostwald ripening is proposed as the mechanism behind the reduction of GB and TB densities at higher temperature, driven by the reduction in interfacial energy and enhancing atomic structural uniformity.
@article{arxiv.2410.06540,
title = {Understanding High Coercivity in ThMn12-Type Sm-Zr-Fe-Co-Ti Permanent Magnet Powders through Nanoscale Analysis},
author = {Nikita Polin and Alexander M. Gabay and Chaoya Han and Christopher Chan and Se-Ho Kim and Chaoyang Ni and Oliver Gutfleisch and George C. Hadjipanayis and Baptiste Gault},
journal= {arXiv preprint arXiv:2410.06540},
year = {2024}
}