Effect of CoFe dusting layer and annealing on the magnetic properties of sputtered Ta/W/CoFeB/CoFe/MgO layer structures

Abstract

We explored the effect of a CoFe wedge inserted as a dusting layer (0.2 nm-0.4 nm thick) at the CoFeB/MgO interface of a sputtered Ta(2 nm)/W(3 nm)/CoFeB(0.9 nm)/MgO(3 nm)/ Ta(2 nm) film-a typical structure for spinorbit torque devices. Films were annealed at temperatures varying between 300 °C and 400 °C in an argon environment. Ferromagnetic resonance studies and vibrating sample magnetometry measurements were carried out to estimate the effective anisotropy field, the Gilbert damping, the saturation magnetization and the dead layer thickness as a function of the CoFe thickness and across several annealing temperatures. While the asdeposited films present only easyplane anisotropy, a transition along the wedge from inplane to outofplane was observed across several annealing temperatures, with evidence of a spinreorientation transition separating the two regions.

High temperature stability in few atomic layer MoS2 based thin film heterostructures: structural, static and dynamic magnetization properties

“…Notably, the heterostructures with CoFeB as FM are comparatively more versatile due to the fact that the fabrication of SOT based spintronic devices often necessitates processing at high temperatures ∼300 °C-400 °C. 19,20…”

“…In addition to this, spintronic devices must have high thermal endurance and maintain their magnetic properties at high temperatures. 19,20 On the other hand, most of the HMs (Ta, W, etc.) and their alloys are susceptible to interdiffusion during post-thermal annealing (T A ) in the layered stack around 300 °C.…”

“…Thus, the current study helps to promote the MoS 2 /CoFeB bilayer combination capable of exhibiting acceptable high spin-pumping and good thermal stability. 19,20 This study is essential due to the fact that the fabrication of SOT-based spintronic devices has various impacts and requires processing at high temperatures of approximately 300 °C to 400 °C.…”

Impact of Fe80B20 insertion on the properties of dual-MgO perpendicular magnetic tunnel junctions

“…For bottom FeB insertion (figure 5(b)), however, 𝛼 reaches the minimum at 0.4 nm FeB insertion and increases dramatically beyond the measurement range with the FeB thickness in both annealing conditions. For those cases, the resonance is too broadened to be resolved, reflecting a very large damping [21]. It also leads to a huge uncertainty in the resonance field and hence 𝜇 𝐻 determination, as mentioned in the preivous section.…”

“…Other works examined the effect of element (Fe or B) composition in CoFeB layers in MTJ stacks on several parameters, including tunnel magneto-resistance (TMR) [16], PMA [17][18][19], and annealing stability [20]. It has been demonstrated that a thickness gradient in the B content can modify the properties of CoFeB/MgO bilayer system such as damping and anisotropy [21]. PMA of the FL was also reported to be improved with increasing the Fe composition in CoFeB, on which its TMR is almost independent [22].…”