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Magnetic transition in ultrathin Co sandwiched between Au layers in [Au (3.16 nm)/Co (1.5 nm)] x 35 /Si(100) multilayers
Author(s) -
Tripathi Jitendra,
Sharma Anupam,
Kumar Dileep,
Singh Jaiveer,
Bisen Rishabh,
Tripathi Shilpa
Publication year - 2021
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.6910
Subject(s) - superparamagnetism , annealing (glass) , materials science , ferromagnetism , bilayer , transition metal , diffraction , condensed matter physics , crystallography , magnetization , chemistry , optics , magnetic field , metallurgy , catalysis , biochemistry , physics , quantum mechanics , membrane
The superparamagnetic to ferromagnetic transition in ultrathin Co layers has been investigated by systematic annealing of Co ultrathin layer sandwiched between a pair of Au layer in the [Au (3.16 nm)/Co (1.5 nm)] x 35 /Si(100) multilayers. Apart from this magnetic transition, annealing‐induced modifications in morphological and structural properties of this discontinuous island like Co ultrathin layer have also been investigated. The thickness and number of Co and Au layers were so chosen as to make a composition of 20 weight percent (wt%) Co in Au matrix. X‐ray diffraction and reflectivity measurements reveal the formation of a bilayer stack showing Bragg's peaks, which disappear upon annealing beyond 200°C due to mixing of layers. Corresponding SQUID results show a transition from superparamagnetic to ferromagnetic phase beyond 200°C, indicating the clusterization of Co, which is enabled by nonmiscible nature of Co and Au. The results are interpreted in terms of annealing‐dependent mobility of Co and Au atoms resulting in superparamagnetic to ferromagnetic and finally to a non‐magnetic phase.