Lattice relaxation studies in strained epitaxial Fe-Co-C films

Abstract

Extraordinarily large perpendicular magnetic anisotropy in epitaxially strained cobalt-ferrite CoxFe3−xO4(001) (x = 0.75, 1.0) thin films Appl.

Challenges toward development of rear‐earth free FeCo based permanent magnet

“…In order to stabilize bct structure above the thickness limit of method A ( t > 5 nm), our research group examined effects of adding various third elements as method B 24 . Other researchers also reported on results of third element addition including C, 19 B, 20 Ti, 21 and Mo 32 . Here we explain about effects of V and N addition as previously reported by our group in a patent application dated 2017 25 and a paper dated 2019 23 .…”

“…Giant magnetic anisotropy of FeCo compounds was theoretically predicted in 2004; 4 after that, the prediction was proven via a number of experiments with thin films 11–25 . This giant magnetic anisotropy can be explained by tetragonalization of the crystal structure and modification of the band structure 4 .…”

“…Giant magnetic anisotropy of FeCo compounds was theoretically predicted in 2004; 4 after that, the prediction was proven via a number of experiments with thin films. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] This giant magnetic anisotropy can be explained by tetragonalization of the crystal structure and modification of the band structure. 4 However, at the time of writing, almost all experiments were conducted on thin films, and one can assume that the greatest practical challenge is fabrication of bulk materials.…”

Structural and magnetic properties of strongly carbon doped Fe–Co thin films

“…It is expected that films with lower thickness can exhibit slightly higher strain. In a recent publication byReichel et al [7,19], observed c/a ratios of up to. 1.05 in Fe-Co-C films with 2 at% C with 5 nm thickness.…”

Designing Rare-Earth Free Permanent Magnets in Heusler Alloys Via Interstitial Doping

“…Nevertheless, due to the strong tendency for the FeCo alloys to relax, it is difficult to maintain the tetragonal distortion induced by the underlying substrates for thin films thicker than 2 nm [6,7,8]. Recently, following the prediction based on DFT calculations [9,10], systematic studies have been performed on FeCo+X (X= C and B), where spontaneous tetragonal distortions with c/a=1.04 can be induced by a few atomic percent interstitial doping of C or B atoms occupying the octahedral interstitial sites. The resulting MAE can be as large as 0.5 MJ/m 3 with B concentration up to 4 at%, where the tetragonal strain reaches 5%.…”