Abstract
The magnetic anisotropy energy for core–shell α”-Fe16N2 nanoparticles was evaluated by the rotational hysteresis loss obtained from magnetic torque measurements. The saturation magnetization of the α”-Fe16N2 core was deduced from volume fractions of α”-Fe16N2 determined by an analysis of a low-temperature Mossbauer spectrum. The saturation magnetization and the anisotropy energy were found to be 234 emu/cc and 6.9 Merg/cm3, respectively. These values coincide with those of bulk-like single-phase α”-Fe16N2 particles. This crystalline anisotropy is still smaller than the shape anisotropy of the thin films (2πMs2=20 Merg/cm3), and a perpendicular magnetic state is not expected for the thin-film form.
Highlights
Fe nitrides have a variety of crystalline structures corresponding to the concentration of nitrogen.There are a few ferromagnetic nitrides, and many of these have been studied from the viewpoint of magnetic materials.[1,2] Early-stage efforts for developing magnetic materials focused on applications for magnetic recording tape media using Fe4N pigments[3] and recently as a candidate for a spintronics material with a half-metallic electronic structure.[4] α”-Fe16N2 has a tetragonally distorted structure, in which one of the axes is elongated and the nitrogen atoms are ordered
We have reported that the Ku of the core–shell α”-Fe16N2 NP, estimated from typical torque measurements, is 4.4 x 106 erg/cm3.10
Because the NPs have a core–shell type structure, where a nonmagnetic oxide layer covers the α”-Fe16N2 cores, the low-temperature Mossbauer spectra were analyzed to estimate the magnetization of this portion of the α”-Fe16N2 cores from the ratio of nitrides and oxides, and Ku was deduced from these values
Summary
Fe nitrides have a variety of crystalline structures corresponding to the concentration of nitrogen.There are a few ferromagnetic nitrides, and many of these have been studied from the viewpoint of magnetic materials.[1,2] Early-stage efforts for developing magnetic materials focused on applications for magnetic recording tape media using Fe4N pigments[3] and recently as a candidate for a spintronics material with a half-metallic electronic structure.[4] α”-Fe16N2 has a tetragonally distorted structure, in which one of the axes is elongated and the nitrogen atoms are ordered. Because the NPs have a core–shell type structure, where a nonmagnetic oxide layer covers the α”-Fe16N2 cores, the low-temperature Mossbauer spectra were analyzed to estimate the magnetization of this portion of the α”-Fe16N2 cores from the ratio of nitrides and oxides, and Ku was deduced from these values.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
