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"Tailoring thermal stability and in-plane magnetic anisotropy of CoFeB alloy thin films via growth conditions engineering".

"Tailoring thermal stability and in-plane magnetic anisotropy of CoFeB alloy thin films via growth conditions engineering".

Authors :
Gupta, Neha
Gupta, Mukul
Kumar, D.
Rai, Sanjay
Gupta, Pooja
Source :
Intermetallics. Mar2024, Vol. 166, pN.PAG-N.PAG. 1p.
Publication Year :
2024

Abstract

The present work investigates the influence of growth conditions on the magneto-structural properties of magnetron-sputtered CoFeB alloy thin films. Films grown at room temperature (RT) are soft magnetic (coercivity <9 Oe), show amorphous microstructure, and possess a distinct uniaxial magnetic anisotropy (UMA) in the film plane. The amorphous microstructure and UMA persist up to a growth temperature (Ts) of 300 °C. CoFeB film grown at Si (100) substrate shows amorphous to crystalline phase transformation at Ts = 500 °C. In contrast, under the same growth conditions, the CoFeB film prepared on the SiO 2 substrate maintains an amorphous structure up to Ts = 500 °C. The difference in the microstructures was explained in terms of the out-diffusion of B to the interfacial layer and segregation near the substrate for the films having crystalline and amorphous structure, respectively. On both the substrates Addition of W buffer layer facilitated the growth of smooth and nanocrystalline CoFeB films at Ts ∼300 °C. Upon crystallization, UMA evolution with a simultaneous increase in the coercive field is interpreted in terms of joint effect of random anisotropy model and surface/interface roughness-induced magnetization reversal mechanism. Unlike post-annealing, the CoFeB films prepared at high temperature shows superior thermal stability against crystallization. The relationship between the soft magnetic performance, UMA evolution, and thermal stability of CoFeB films with the growth conditions is established. The study reveals the role of growth condition engineering, to obtain CoFeB thin films with controlled microstructure and magnetic performance, which is crucial for designing the spintronics devices. • Growth conditions such as temperature, substrate and buffer layer were varied to deposit CoFeB thin films were successfully prepared. • On SiO 2 substrate films remained amorphous, soft magnetic and persist UMA up to Ts = 500 °C • In comparision to post annealing, gowth temperature variation results in thermally stable film structure. • At high temperature, B distribution dictates the final microstructure. • W buffer layer addition result in smooth CoFeB film with improved crystalline quality. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09669795
Volume :
166
Database :
Academic Search Index
Journal :
Intermetallics
Publication Type :
Academic Journal
Accession number :
175242557
Full Text :
https://doi.org/10.1016/j.intermet.2024.108195