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We report on Boron diffusion and subsequent crystallization of Co40Fe40B20 (CoFeB) thin films on SiO2/Si (001) substrate using pulsed laser deposition. Secondary ion mass spectroscopy reveals Boron diffusion at the interface in both amorphous and crystalline phase of CoFeB. High-resolution transmission electron microscopy reveals a small fraction of nano-crystallites embedded in the amorphous matrix of CoFeB. However, annealing at 400◦ C results in crystallization of CoFe with bcc structure along (110) orientation. As-deposited films are non-metallic in nature with the coercivity (Hc) of 5Oe while the films annealed at 400◦ C are metallic with a Hc of 135Oe. C с 2013 Author (s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.[http://dx. doi. org/10.1063/1.4816811](CoxFe1− x) 80B20 alloys have been under extensive research focus due to high tunneling magnetoresistance (TMR) and perpendicular magnetic anisotropy (PMA) observed in thin films of this material combined with ultrathin MgO layer. 1–4 A controlled transition of CoFeB from amorphous to crystalline phase is a necessary condition for the observation of giant TMR effect. 1–3 By post deposition thermal annealing in vacuum, TMR of the CoFeB based magnetic tunnel junctions (MTJs) increases abruptly. 3 Furthermore, recent results 4 have shown that although CoFeB/MgO system is widely used for in-plane anisotropic MTJs, it can also meet the requirements of high thermal stability and low induced current density magnetization switching for high performance perpendicular MTJs. Apart from this, CoFeB …
Publication date: 
1 Jan 2014

G Venkat Swamy, Himanshu Pandey, AK Srivastava, MK Dalai, KK Maurya

Biblio References: 
Volume: 182407 Issue: 10.1063/1.4875927 Pages: 104
Appl. Phys. Lett