Presentation Information
[O13-2]Thin film model study for developing new permanent magnetic material
*Yukiko K Takahashi1 (1. NIMS (Japan))
Keywords:
Sm-Fe-based compound,thin film
With rapid increase of the electrification in various kinds of devices, demand for the permanent magnets with high performance is increasing significantly. There are two potential material systems to realize the sustainable supply of the high performance permanent magnets, rare-earth (RE) lean and RE-free permanent magnets. We have been investigating RE-lean permanent magnets so far since we believe 4f elements are necessary for realizing high anisotropy.
To realize high performance in the permanent magnets, both of the high intrinsic properties such as saturation magnetization (Ms), anisotropy (Ku) and Curie temperature (Tc) and high extrinsic property such as coercivity are necessary. In this presentation, I would like to show our recent material development and microstructure engineering in the thin film as the demonstrative work.
In the development of RE-lean permanent magnet, Sm-Fe based magnetic materials such as 1-7 and 1-12 are the candidates for beyond Nd-Fe based magnet, because it has the potential of high Ms due to high molar fraction of Fe. We successfully prepared Sm-Fe based thin film with the phase of 1-7 and 1-12. Both of them have superior intrinsic magnetic properties to those of Nd2Fe14B.
How to achieve high coercivity (Hc) in these materials? To realize high Hc, the microstructure control for magnetic domain wall motion is important. Well known Nd-Fe based magnet and FePt magnetic recording media give us some hints for high Hc. In the Nd-Fe based magnet, 2-14-1 grains are enveloped by the Nd-rich phase, which act as the pinning of the magnetic domain wall motion. In the case of FePt magnetic recording media, nonmagnetic material is co-sputtered with FePt and form well isolated microstructure and show very high Hc. From these two examples, we have investigated the grain boundary diffusion and co-sputter with nonmagnetic element in 1-12 system.
I would like to discuss how to improve the Hc in 1-12 system by comparing Nd-Fe-B permanent magnet and FePt magnetic recording media. In addition, the intrinsic properties of 1-7 system will be presented.
To realize high performance in the permanent magnets, both of the high intrinsic properties such as saturation magnetization (Ms), anisotropy (Ku) and Curie temperature (Tc) and high extrinsic property such as coercivity are necessary. In this presentation, I would like to show our recent material development and microstructure engineering in the thin film as the demonstrative work.
In the development of RE-lean permanent magnet, Sm-Fe based magnetic materials such as 1-7 and 1-12 are the candidates for beyond Nd-Fe based magnet, because it has the potential of high Ms due to high molar fraction of Fe. We successfully prepared Sm-Fe based thin film with the phase of 1-7 and 1-12. Both of them have superior intrinsic magnetic properties to those of Nd2Fe14B.
How to achieve high coercivity (Hc) in these materials? To realize high Hc, the microstructure control for magnetic domain wall motion is important. Well known Nd-Fe based magnet and FePt magnetic recording media give us some hints for high Hc. In the Nd-Fe based magnet, 2-14-1 grains are enveloped by the Nd-rich phase, which act as the pinning of the magnetic domain wall motion. In the case of FePt magnetic recording media, nonmagnetic material is co-sputtered with FePt and form well isolated microstructure and show very high Hc. From these two examples, we have investigated the grain boundary diffusion and co-sputter with nonmagnetic element in 1-12 system.
I would like to discuss how to improve the Hc in 1-12 system by comparing Nd-Fe-B permanent magnet and FePt magnetic recording media. In addition, the intrinsic properties of 1-7 system will be presented.