Growth-induced non-planar magnetic anisotropy in FeCoZr-CaF2 nanogranular films: Structural and magnetic characterization
AutoriKasiuk, J. V.
Fedotova, J. A.
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The relation between nanoscale structure, local atomic order and magnetic properties of (FeCoZr)(x)(CaF2)(100-x) (29 LT = x LT = 73 at. %) granular films is studied as a function of metal/insulator fraction ratio. The films of a thickness of 1-6 mu m were deposited on Al-foils and glass-ceramic substrates, by ion sputtering of targets of different metal/insulator contents. Structural characterization with X-ray and electron diffraction as well as transmission electron microscopy revealed that the films are composed of isolated nanocrystalline bcc alpha-FeCo(Zr) alloy and insulating fcc CaF2 matrix. They grow in a columnar structure, where elongated metallic nanograins are arranged on top of each other within the columns almost normal to the substrate surface. Mossbauer spectroscopy and magnetometry results indicate that their easy magnetization axes are oriented at an angle of 65 degrees-74 degrees to the surface in films with x between 46 and 74, above the electrical percolation thres...hold, which is attributed to the growth-induced shape anisotropy. Interatomic distances characteristic for metallic state of alpha-FeCo(Zr) nanograins were revealed by X-ray Absorption Spectroscopy. The results show a lack of surface oxidation of the alloy nanograins, so the growth-induced orientation of nanograins in the films cannot be attributed to this effect. The study is among the first to report a growth-induced non-planar magnetic anisotropy in metal/insulator granular films above the percolation threshold and to reveal the origin of it. (C) 2014 AIP Publishing LLC.
Izvor:Journal of Applied Physics, 2014, 116, 4
- SILAMPS - Silicon integrated lasers and optical amplifiers (EU-226470)
- Fizički procesi u sintezi novih nanostrukturnih materijala (RS-171023)
- initiative ELISA: EU Support of Access to Synchrotrons/FELs in Europe, Belarusian State program Functional materials [1.16], Polish Ministry of Science and Higher Education, EU COST Action [MP0903 Nanoalloys]