Micromagnetic study of the effect of Dzyaloshinskii-Moriya interaction on magnetization reversal in magnetic nanodots of different shape

Syamlal, S K; Priyanka, B.; Perumal, Hari Prasanth; Sinha, Jaivardhan

doi:10.1016/j.jmmm.2022.170195

Cited by 3 publications

(1 citation statement)

References 29 publications

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“…The presence of a vortex (one/two) in circular and square voids leads to possibility of large maximum angle between the spins in comparison with the global-vortex state. In a recent study, Syamlal et al explored the estimation of spin canting angles in circular, square, and triangular-shaped Conanostructures with changing the interfacial Dzyaloshinskii-Moriya interaction (DMI) [52]. Their findings highlighted that the triangular nanodot exhibited a significantly larger spin-canting angle compared to square and circular nanodots for a particular at DMI = 3 mJ m −2 , (Triangle: 13°, Circle: 9°, and Square: 8°).…”

Section: Effect Of the Geometry Of Void On Magnetization In Asymmetri...mentioning

confidence: 99%

Effect of void geometry and magnetic anisotropy in controlling the vortex in sub-micron annular Permalloy disc

Palabindela,

Sinha,

Behera

2024

Phys. Scr.

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Ferromagnetic rings, particularly asymmetric Permalloy (Py) rings are recognized as promising configurations for spintronic devices, offering additional degrees of freedom for manipulating magnetic states, especially in vortex configurations. Through micromagnetic simulations, our study explores the impact on magnetization states and spin configuration concerning ring symmetry, aligning with the interest in controlling vortex states for information storage. We initially obtained zero-field spin configurations by varying ring thickness (t), observing a 360° domain wall in rings with t < 12 nm and bi-vortex wall in rings with t ~ 36 nm during magnetization reversal. Notably, an extended stability of the global-vortex state was observed in rings with t > 36 nm, indicating the dominance of global-vortex nucleation in thick asymmetric rings during domain wall movement. We investigate the hysteresis loops and spin configurations by varying the in-plane and out-of-plane anisotropy values. Our findings reveal the presence of multiple vortex cores with different polarities and sense of rotations in the ring for the in-plane anisotropy ~ 30 to ~ 40 kJ/m3. Additionally, a global-vortex with two vortex cores was formed due to demagnetization energy. We analysed the energy profile of stable magnetization states for various t and anisotropy values. Interestingly, the shape of the hysteresis loop changes significantly for the disc containing different shapes of void. Circular and square-shaped geometries suggest that the bi-vortex state is a stable configuration during magnetization reversal in both cases. The study also indicates the stability of the vortex with a square-shaped void geometry up to a sufficiently large field. For the case of triangular-shaped voids, the global-vortex state was favored with even the small fields. The estimated spin canting angles are found to be correlated with the presence of vortex spin configurations. Overall, these results are important for the development of magnetization vortex-based spintronics devices.

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Section: Effect Of the Geometry Of Void On Magnetization In Asymmetri...mentioning

confidence: 99%

Effect of void geometry and magnetic anisotropy in controlling the vortex in sub-micron annular Permalloy disc

Palabindela,

Sinha,

Behera

2024

Phys. Scr.

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Tunable Creation and Annihilation of Magnetic Bimerons in Square-Shaped Submicron Dot

Babu,

Perumal,

Sankaran Kunnath

et al. 2023

ACS Appl. Electron. Mater.

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Recently, the study of nontrivial topological spin textures has gained immense attention due to their fascinating properties such as stability, small size, topological protection, and low drive current density. Magnetic bimeron is one such topological spin texture that has been realized experimentally and theoretically in the past few years. A magnetic bimeron is defined as the topological counterpart of skyrmions in in-plane magnetized systems. In this work, using micromagnetic simulations, we stabilize bimerons in a square-shaped submicrometer dot with in-plane magnetic anisotropy. We first investigate the effect of interfacial Dzyaloshinskii−Moriya interaction (IDMI) on the magnetization reversal mechanism by analyzing the snapshots of the spin configuration and total energy of the system. Our results indicate a monotonic increase in coercive field values and total energy with increasing DMI values (D) from 0 to 3 mJ/m 2 . However, for D = 4 mJ/m 2 , we see the stabilization of bimerons of both of the topological charges (Q = +1 and Q = −1) in the square dot during the magnetization reversal process. We also report that the formation of a bimeron (Q = +1) or an antibimeron (Q = −1) during the reversal can be controlled by the application of a static bias field in addition to the sweeping field. Furthermore, we show the dynamical conversion of a chiral stripe domain into pairs of bimeron and antibimeron in the presence of Zhang−Li type of spintransfer torque. The results presented in this work will be useful in building future spintronic-based devices where bimerons can be used as bits of information carriers.

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Micromagnetic study of exchange bias effect in sub-micron dots of Co₂MnSi interfaced with uncompensated IrMn

Perarasan,

Arunachalam,

Chandramohan

et al. 2024

Phys. Scr.

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Owing to its crucial role in spintronics devices, the exchange bias (EB) phenomenon has been extensively investigated in various ferromagnet (FM) and antiferromagnet (AFM) bilayers since its discovery in Co/CoO core-shell nanoparticles. In this study, we present the emergence of negative EB for the first time in the Co2MnSi Heusler alloy interfacing with an uncompensated AFM, exhibiting analogous anisotropy to the IrMn. Due to the high pinning and IrMn anisotropy values, EB is stronger here. Investigation into the influence of ferromagnetic layer thickness (tFM) on exchange bias reveals an inverse relationship, while coercivity displays a non-monotonic increase. The analysis of spin canting angles suggests the presence of a maximum canting angle in the Co2MnSi layer close to the interface. We thoroughly analyze the spin configurations at the interface as well as away from it in the Co2MnSi (25 nm)/IrMn (5 nm) bilayer to better understand the mechanism of magnetization reversal. Interestingly, our findings unveiled distinct spin behaviors for the first and second reversals. In cases of small AFM thicknesses (tAFM), the exchange field is proportionate to the tAFM, contrasting with large tAFM, where it scales as 1/tAFM. Notably, coercivity demonstrates an increasing behavior across all tAFM variations. The angular dependence of the Heusler alloy revealed a four-fold symmetry indicative of cubic anisotropy and a two-fold symmetry representative of uniaxial anisotropy. The angular dependency study of exchange bias indicated similar clockwise and counterclockwise rotations, with cos (θ) unidirectional dependence. However, loop shifting revealed that the lower pinning ability at 00 was due to a low Meiklejohn-Bean parameter (R) value. Additionally, through the manipulation of the R-parameter, we can tune the magnitude of the coercive field and EB. All these results are crucial for the utilization of the Co2MnSi/IrMn heterostructures for various applications in spintronics-based devices.

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Micromagnetic study of the effect of Dzyaloshinskii-Moriya interaction on magnetization reversal in magnetic nanodots of different shape

Cited by 3 publications

References 29 publications

Effect of void geometry and magnetic anisotropy in controlling the vortex in sub-micron annular Permalloy disc

Effect of void geometry and magnetic anisotropy in controlling the vortex in sub-micron annular Permalloy disc

Tunable Creation and Annihilation of Magnetic Bimerons in Square-Shaped Submicron Dot

Micromagnetic study of exchange bias effect in sub-micron dots of Co₂MnSi interfaced with uncompensated IrMn

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Micromagnetic study of the effect of Dzyaloshinskii-Moriya interaction on magnetization reversal in magnetic nanodots of different shape

Cited by 3 publications

References 29 publications

Effect of void geometry and magnetic anisotropy in controlling the vortex in sub-micron annular Permalloy disc

Effect of void geometry and magnetic anisotropy in controlling the vortex in sub-micron annular Permalloy disc

Tunable Creation and Annihilation of Magnetic Bimerons in Square-Shaped Submicron Dot

Micromagnetic study of exchange bias effect in sub-micron dots of Co2MnSi interfaced with uncompensated IrMn

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Micromagnetic study of exchange bias effect in sub-micron dots of Co₂MnSi interfaced with uncompensated IrMn