Multiscale modeling of spin transport across a diffuse interface

Chureemart, J.; Cuadrado, R.; Chureemart, P.; Chantrell, R.W.

doi:10.1016/j.jmmm.2017.07.085

Cited by 4 publications

(6 citation statements)

References 30 publications

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“…where V cell is the microcell volume, j m is the spin current and e is the electron charge. The value of k B T used here [41,31] is 10 meV or 1.6 × 10 −21 J. Subsequently, the total RA of the system is calculated by summing the resistance of all microcells, RA = ∑ n i=1 RA i where n is the number of microcells.…”

Section: Model Descriptionmentioning

confidence: 99%

Large magnetoresistance in Heusler alloy-based current perpendicular to plane giant magnetoresistance sensors

Saenphum¹,

Chureemart²,

Evans³

et al. 2021

J. Phys. D: Appl. Phys.

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Increasing the data storage in next-generation hard disk drives requires a reduction in the physical dimensions of read sensors. Tunneling magnetoresistance (TMR) heads yield high magnetoresistance (MR) ratio but with a high resistance-area product (RA) that is suboptimal for devices. Giant magnetoresistance (GMR) head with different materials is an alternative way to improve reader performance with high MR ratio and low RA. In this paper, we theoretically study the effect of material properties and the layer thickness on RA and MR ratio in a trilayer system via an atomistic model combined with the spin transport model. The GMR stack can be constructed by the atomistic model and the RA and MR ratio can be directly calculated by considering the spin accumulation and spin current from the spin transport model. It is found that the spin valve using the Co 2 FeAl Heusler alloy electrode with high spin polarization exhibits a high MR ratio and RA of 64 mΩ • µm 2 which is better than the spin valves using conventional ferromagnets (FM) such as Co, NiFe and CoFe. Moreover, we consider the thickness dependence of the change of RA (∆RA). Increasing the free layer thickness yields the increase in ∆RA and MR ratio because of the enhancement of the bulk spin scattering. Additionally, the results show that the △RA depends on the spin diffusion length of the nonmagnetic materials (λ sdl,NM ). The ∆RA increases from 3 up to 10 mΩ • µm 2 when λ sdl,NM increases from 35 to 1200 nm. This investigation shows the possibility for read head design of HDDs with areal density beyond 2 Tb/in 2 .

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Section: Model Descriptionmentioning

confidence: 99%

Large magnetoresistance in Heusler alloy-based current perpendicular to plane giant magnetoresistance sensors

Saenphum¹,

Chureemart²,

Evans³

et al. 2021

J. Phys. D: Appl. Phys.

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“…The investigation of the magnetization reversal driven by spin-transfer torque can be achieved using the self-consistent solution of spin accumulation and spin current (j m ), which is written as follows [31,[36][37][38]:…”

Section: Methodsmentioning

confidence: 99%

Heusler-alloy-based magnetoresistive sensor with synthetic antiferromagnet

Khamtawi,

Saenphum,

Chantrell

et al. 2023

J. Phys. D: Appl. Phys.

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Heusler alloy has been widely utilized in magnetoresistive sensors to enhance the device performance. In this work, we theoretically investigate the performance of Heusler-alloy-based magnetoresistive sensors with a synthetic antiferromagnet (SAF) layer. The atomistic model combined with the spin accumulation model will be used in this work. The former is used to construct the reader stack and investigate the magnetization dynamics in the system. The latter is employed to describe the spin transport behavior at any position of the structure. We first perform simulations of the exchange bias (EB) phenomenon in the IrMn/ C o 2 F e S i (CFS) system providing a high EB field. Then, a realistic reader stack of IrMn/CFS/Ru/CFS/Ag/CFS is constructed via an atomistic model. Subsequently, the resistance–area product (RA) and magnetoresistance (MR) ratio of the reader can be calculated by using the spin accumulation model. As a result of the spin transport behavior in the Heusler-alloy-based reader stack including SAF structure at 0 K, an enhancement of the MR ratio up to 120 % and RA < 40 m Ω ⋅ μ m 2 can be observed. This study demonstrates the important role of the Heusler alloy and SAF layer in the development of magnetoresistive sensors for the application of readers in hard disk drives with an areal density beyond 2 Tb in−2.

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“…Such ultrafast optical control of magnetic states renders it a promising technology for spintronic devices. Despite tremendous experimental progress in this field (2, 3, 11, 12, 14-20, 22, 26-29), the fundamental physics remains unclear, and there are long-standing debates over the dominant mechanisms for the ultrafast demagnetization process (10,20,21,(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42). A variety of different mechanisms have been proposed in the last 20 years.…”

Section: Introductionmentioning

confidence: 99%

Light-induced ultrafast spin transport in multilayer metallic films originates from sp - d spin exchange coupling

Chen,

Luo,

Wang

2023

Sci. Adv.

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Ultrafast interaction between the femtosecond laser pulse and the magnetic metal provides an efficient way to manipulate the magnetic states of matter. Numerous experimental advancements have been made on multilayer metallic films in the last two decades. However, the underlying physics remains unclear. Here, relying on an efficient ab initio spin dynamics simulation algorithm, we revealed the physics that can unify the progress in different experiments. We found that light-induced ultrafast spin transport in multilayer metallic films originates from the sp - d spin-exchange interaction, which can induce an ultrafast, large, and pure spin current from ferromagnetic metal to nonmagnetic metal without charge carrier transport. The resulting trends of spin demagnetization and spin flow are consistent with most experiments. It can explain a variety of ultrafast light-spin manipulation experiments with different systems and different pump-probe technologies, covering a wide range of work in this field.

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Multiscale modeling of spin transport across a diffuse interface

Cited by 4 publications

References 30 publications

Large magnetoresistance in Heusler alloy-based current perpendicular to plane giant magnetoresistance sensors

Large magnetoresistance in Heusler alloy-based current perpendicular to plane giant magnetoresistance sensors

Heusler-alloy-based magnetoresistive sensor with synthetic antiferromagnet

Light-induced ultrafast spin transport in multilayer metallic films originates from sp - d spin exchange coupling

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