Magnetization dynamics and interface studies in ion-beam sputtered Si/CoFeB(8)/MgO(4)/CoFeB(8)/Ta(5) structures

Raju, M.; Behera, Nilamani; Pandya, Dinesh K.; Chaudhary, Sujeet

doi:10.1063/1.4863804

Cited by 8 publications

(7 citation statements)

References 18 publications

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“…This conclusion is well supported by the fact that the angles of measured fringe peak positions for as‐deposited and low‐temperature‐annealed samples are in good agreement . However, following very‐high‐temperature annealing, the thickness of Ta increases due to absorption of O in the Ta layer from both MgO and the annealing environment, whereas the MgO thickness decreases due to degradation of the MgO layer; these explanations for the observed changes are also supported by the reduced fringe periodicity in Figure C . The upper Ta 2 O 5 layers have a slightly higher density than the bulk material (8.20 gm/cc), whereas the lower Ta 2 O 5 layers have a slightly lower density than metallic Ta (16.60 gm/cc).…”

Section: Resultssupporting

confidence: 59%

Characterization of the interfacial structure and perpendicular magnetic anisotropy in CoFeB‐MgO structures with different buffer layers

Shi

Fang

et al. 2017

Surface & Interface Analysis

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In this study, we describe the deposition of Hf and Mo metal layers individually on Ta to compose new buffer layers, ie, Ta/Hf and Ta/Mo, where CoFeB/MgO stacks are deposited using magnetron sputtering. The synthesised Ta/Hf buffer has higher surface roughness, while the Ta/Mo buffer has lower surface roughness as compared with the Ta buffer. The surface roughness of the buffer appears to influence the interface of the subsequently deposited layers, resulting in rougher or smoother CoFeB/MgO interfaces. Additionally, we present a report on the magnetic properties of Ta, Ta/Hf, and Ta/Mo buffer samples. As the annealing temperature is below 200°C, the saturation magnetisation (Ms) values for all buffer layers increase at similar rates, whereas the effective magnetic anisotropy energy (K eff ) values increase at varying rates. After annealing at 350°C, K eff reaches its maximum value for Ta/Hf and Ta/Mo buffer layers, whereas the CoFeB/MgO interface width decreases to a minimum value. The width increases as the annealing temperature is increased over 350°C, and K eff gradually decreases with increase in the annealing temperature. The CoFeB/MgO interface width is primarily dependent on the buffer/CoFeB interface width, which is a critical parameter to obtain high perpendicular magnetic anisotropy (PMA) and high-quality films. This work provides perspectives for understanding and controlling PMA from the viewpoint of interfacial structure. Subsequent studies found that the observed PMA in Ta/CoFeB/MgO sandwiches originates primarily from the CoFeB/MgO interface. 1,[4][5][6][7] More recently, the CoFeB/nonmagnetic metal counter interface has been reported to also affect the perpendicular anisotropy originating from CoFeB/MgO. [7][8][9][10][11][12] Typically, the thickness of CoFeB must be less than 1.5 nm in order to obtain a perpendicular easy axis. 1,8,12 Owing to the limitations on the required thickness, any influence of the counter interfaces of CoFeB with the buffer layer and MgO on the structural, morphological, and PMA properties of CoFeB layers warrants careful investigation.In the X-ray reflectivity (XRR) measurement conducted herein, we use Cu as the anode material and an X-ray wavelength of 0.154 nm to investigate the interface till submonolayer resolution in terms of roughness and/or intermixing. 13 XRR and atomic force microscopy (AFM) measurements were used to analyse changes in the interface structure during annealing.

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Section: Resultssupporting

confidence: 59%

Characterization of the interfacial structure and perpendicular magnetic anisotropy in CoFeB‐MgO structures with different buffer layers

Shi

Fang

et al. 2017

Surface & Interface Analysis

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“…The thickness of each layer matches with the assumed (or nominal) value quite well and the low interface roughness of the films suggests that there is no intermixing between CFB and Ta in our films. Also, we have previously reported the cross-sectional measurement where no interface mixing was observed [32]. It should be noted that interface roughness has a very crucial impact on spin pumping and also ferromagnetic coupling.…”

Section: B X-ray Reflectivity (Xrr) Studymentioning

confidence: 80%

Impact of ferromagnetic layer thickness on the spin pumping in Co60Fe20B20/Ta bilayer thin films

Hait

Husain

Gupta

et al. 2021

J Mater Sci: Mater Electron

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in step of 1nm) using ion-beam sputtering technique.2. Structural and morphological study using X-ray diffraction (XRD), X-ray reflectivity (XRR), Atomic Force Microscopy (AFM) and Energy Dispersive X-ray (EDX) analysis.3. A detailed analysis of spin pumping based on range of Co60Fe20B20 and Ta thicknesses.4. Low thicknesses of Co60Fe20B20 (4 & 6nm) follow normal spin pumping behaviour while anomaly is present in thick Co60Fe20B20 (8nm) film heterostructure.

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“…Synthetic antiferromagnets (SAFs) with perpendicular anisotropy (p-SAF) have been designed to be used for applications in magnetic memory and data storage elements engineering. Domain-wall dynamics in systems with perpendicular magnetic anisotropy (PMA) attracts much attention for fundamental studies and potential applications [1,2]. Indeed, domain-wall motion in thin magnetic films provides interesting opportunities for the design of high-performance spintronics devices [1] such as racetrack memories [2], domain-wall logic circuits [3], and domain-wall nano-oscillators [4].…”

Section: Introductionmentioning

confidence: 99%

“…Now we would like to focus on the magnetization dynamics during the transition from one magnetic state to the other. Domain-wall dynamics in p-SAF systems is very unusual [1,2] and becomes more complicated for multilayered samples.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic aftereffects in CoFeB/Ta/CoFeB spin valves of large area

et al. 2017

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Magnetic aftereffect measurements on a synthetic antiferromagnet with strong perpendicular anisotropy are presented. Two types of magnetic transitions are observed in the CoFeB/Ta/CoFeB bilayer where the two ferromagnetic CoFeB layers are antiferromagnetically coupled: the transition from a parallel to an antiparallel CoFeB layers magnetization alignment and the transition between two possible antiparallel magnetization states. Magnetic relaxation measurements show a complete reversal in the case of the transition between the two antiferromagnetic configurations. The experimental data can be well fitted in the frame of extended exponential relaxation using the Fatuzzo-Labrune model. Consequently, the domain nucleation and domain-wall propagation can be studied as a function of temperature and applied field.

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Magnetization dynamics and interface studies in ion-beam sputtered Si/CoFeB(8)/MgO(4)/CoFeB(8)/Ta(5) structures

Cited by 8 publications

References 18 publications

Characterization of the interfacial structure and perpendicular magnetic anisotropy in CoFeB‐MgO structures with different buffer layers

Characterization of the interfacial structure and perpendicular magnetic anisotropy in CoFeB‐MgO structures with different buffer layers

Impact of ferromagnetic layer thickness on the spin pumping in Co60Fe20B20/Ta bilayer thin films

Magnetic aftereffects in CoFeB/Ta/CoFeB spin valves of large area

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