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Growth and adhesion of biphasic crystalline–amorphous Sm/FeTaN magnetic nanospheroids on a Ta surface
Author(s) -
Cefalas A. C.,
Kovač J.,
Sarantopoulou E.,
Dražić G.,
Kollia Z.,
Kobe S.
Publication year - 2008
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.2752
Subject(s) - amorphous solid , intermetallic , materials science , contact angle , substrate (aquarium) , adhesion , composite material , alloy , analytical chemistry (journal) , crystallography , chemical engineering , chemistry , organic chemistry , oceanography , engineering , geology
The adhesion strength of magnetic films of intermetallic alloys on different substrates specifies their long‐term magnetic functionality, among other physicochemical characteristics of the films. Nanospheroids of Sm/FeTaN intermetallic alloys were grown from the Sm 13.8 Fe 82.2 Ta 4.0 target by pulse laser deposition at 157 nm. The high‐temperature, liquefied nanodroplets were formed in the plume. They eventually solidified on the surface of a Ta substrate covered with a thin Ta/O layer in the form of biphasic nanospheroids, consisting of a crystalline nucleus surrounded by an amorphous mantle. Such nanostructures exhibit a ferromagnetic response because the oxidization of the inner crystalloid nucleus, which specifies the magnetic properties, is prevented by the amorphous spheroid mantle. The strength of adhesion of the nanodroplets on the Ta substrate was inversely proportional to the Sm/Fe concentration. The nanodroplets with high Sm/Fe concentration were bound on the Ta substrate with a large average contact angle of ∼161.4° due to the strong intermolecular forces in the alloy. The nanodroplets with low Sm/Fe concentration exhibited hydrophilic binding, and they were strongly attached to the Ta substrate with an average contact angle of 11.3° . Magnetic force microscopy measurements revealed that the magnetic response of the nanospheroids was proportional to the contact angle. Copyright © 2008 John Wiley & Sons, Ltd.