Synthesis of Fe/sub 16/N/sub 2/ films by using reactive plasma

Magnetic properties and structural implications for nanocrystallineFe−Ti−Nthin films

“…18 Reported values of the saturation induction of the '' α phase vary over a wide range, typically from 20 to 30 kG or so. [13][14][15]20 Neither the details on this bcc-bct transition point nor the problem with the wide variance in 4 at. %, the orthorhombic ς − Fe-N phase forms.…”

“…While the nitrogen is generally taken to reside on interstitial sites and result in an expansion of the iron lattice, 12 the actual effect of the nitrogen atoms on the magnetization is still a matter of controversy. [13][14][15] The shift in interest to the three element Fe-Q-N film system has been driven by the realization that small amounts of the third element can provide an enhanced thermal stability. 16,17 In addition to the challenges to understand the fundamental magnetic properties of Fe-Q-N films, the system shows a number of attractive properties for microwave device and magnetic information storage applications.…”

Theoretical investigation into the possibility of very large moments in Fe16N2

“…However, it took another 20 years for the result to be reproduced (and, in fact, surpassed) by Sugita et al 3,4 Throughout the 1980s and '90s, other measurements of Fe 16 N 2 thin films were reported that generally did not find this large magnetic moment. [5][6][7][8] Concurrently, density-functional theory (DFT) electronic structure calculations were performed, 9-14 finding the moment per Fe ion to be modestly increased with respect to bulk bcc Fe but far short of the 3.5 µ B reported by Sugita et al It was shown 15 that LSDA+U 18 calculations could yield an average moment comparable to that of some experiments (∼ 2.8µ B per Fe), but the parameters (U ≈ 3.94, 1.0, and 1.34 eV on the 4d, 4e, and 8h sites, respectively, with J = U/10) were obtained via an embedded-cluster method with a small screening constant and were not calculated from first principles. Additionally, the J parameter is smaller than usually considered appropriate for transition metals (typically one chooses either an atomic-like J of about 0.9 eV or else a more screened J of about 0.6-0.7 eV).…”

Morphology and magnetic properties of α”-Fe₁₆N₂ nanoparticles synthesized from iron hydroxide and iron oxides

“…After a surprising first report where the α"-Fe16N2 phase exhibited giant saturation magnetization as a thin film 1) , many researches have attempted to produce single phase α"-Fe16N2 2,3) . In 1993, a thin film method was established to achieve a relatively high volume fraction of α"-Fe16N2 using reactive sputtering, where a saturation magnetization of Ms ≃ 240 emu/g and uniaxial magnetocrystalline anisotropy constant of Ku ≃ 1×10 7 erg/cm 3 were determined 4) . These values are very attractive with respect to the realization of a permanent magnet based on this material.…”