An extraordinary chiral exchange-bias phenomenon: engineering the sign of the bias field in orthogonal bilayers by a magnetically switchable response mechanism

Bollero, A.; Neu, V.; Baltz, Vincent; Serantes, David; Cuñado, J. L. F.; Pedrosa, Javier; Palmero, Ester M.; Seifert, Marietta; Diény, B.; Real, R. P. del; Vázquez, M.; Chubykalo‐Fesenko, O.; Camarero, Julio

doi:10.1039/c9nr08852k

Cited by 9 publications

(9 citation statements)

References 42 publications

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“…The possibility of tailoring DMI in SAFs makes them extremely interesting for applications of chiral magnetism and topological spin structures (Legrand et al, 2020;Vedmedenko et al, 2020). Since this topic goes slightly beyond the review, it is not included in the tables, however it is worth mentioning the upcoming interest in SAFs (Bollero et al, 2020;Fernández-Pacheco et al, 2019;Han et al, 2019;Meijer et al, 2020;Tanaka et al, 2020;Tsurkan and Zakeri, 2020).…”

Section: Outlook and Conclusionmentioning

confidence: 99%

Measuring interfacial Dzyaloshinskii-Moriya interaction in ultra-thin magnetic films

Kuepferling¹,

Casiraghi²,

Soares³

et al. 2020

Preprint

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The Dzyaloshinskii-Moriya interaction (DMI), being one of the origins for chiral magnetism, is currently attracting huge attention in the research community focusing on applied magnetism and spintronics. For future applications an accurate measurement of its strength is indispensable. In this work, we present a review of the state of the art of measuring the coefficient D of the Dzyaloshinskii-Moriya interaction, the DMI constant, focusing on systems where the interaction arises from the interface between two materials. The measurement techniques are divided into three categories: a) domain wall based measurements, b) spin wave based measurements and c) spin orbit torque based measurements. We give an overview of the experimental techniques as well as their theoretical background and models for the quantification of the DMI constant D. We analyze the advantages and disadvantages of each method and compare D values in different stacks. The review aims to obtain a better understanding of the applicability of the different techniques to different stacks and of the origin of apparent disagreement of literature values.

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Section: Outlook and Conclusionmentioning

confidence: 99%

Measuring interfacial Dzyaloshinskii-Moriya interaction in ultra-thin magnetic films

Kuepferling¹,

Casiraghi²,

Soares³

et al. 2020

Preprint

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“…In these systems, exchange bias appears when the (Pt/Co) multilayer is in a multidomain configuration and results from interfacial exchange interaction between the in-plane polarized closure domains of the (Pt/Co) multilayer and the NiFe magnetization. Similarly, exchange bias was observed in FeCoB in-plane magnetized layer, exchange coupled to out-of-plane magnetized SmCo 5 FM [16].…”

Section: Introductionmentioning

confidence: 62%

Comparison of stable spin textures in in-plane vs. out-of-plane magnetized exchange-biased multilayers

Dieny,

Fruchart,

Marinero

2024

J. Phys. D: Appl. Phys.

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This paper delves into the origins and specificity of the unique stable spin textures (360° closed loop domain walls and skyrmions) observed in exchange-biased systems, with either in-plane or out-of-plane magnetic anisotropy. In the case of skyrmions, which are nanometer-sized bubbles consisting of closed-loop 180° walls in perpendicularly-magnetized media, the stability of these spin textures arises from the existence of Dzyaloshinskii-Moriya Interactions (DMI). These interactions induce chirality of the domain walls, yielding to some extent a so-called topological protection. More complex structures such as skyrmoniums have been observed, consisting of closed loop 360° walls. Recently, skyrmions formed in the absence of an applied external magnetic field have been stabilized in exchange biased out-of-plane magnetized systems. About two decades ago, another type of stable spin-textures were observed in exchange biased systems, with in-plane magnetization, in particular in the pinned reference layer of spin-valves. These textures consist of 360°-domain-wall rings, the stability of which arises from the easy-plane shape anisotropy of these layers. In this paper, we compare these spin-textures and highlight the similarities and differences in their formation, structure and origin of their stability.

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“…protons, electrons, nuclei, etc), are ubiquitous and play a nonnegligible role, especially in ferromagnetic nanostructures. Many researchers have investigated the relationship between dipolar interactions and exchange bias [27][28][29][30][31][32][33]. González et al [27] found that an oscillatory exchange bias field measured under a maximum value of 0.8 T is due to the interphase dipolar interactions.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, in SmCo 5 (30 nm)/spacer (t spacer = 4.3/12.8 nm)/CoFeB (3 nm) multilayers, dipolar interactions induced the loop shift of several milli-teslas (mT), and the shift direction, i.e. the sign of the exchange bias field, can be controlled by the magnetization of SmCo 5 [32]. Commonly, in conventional materials, where the atomic magnetic moments sit on the crystallographic lattice sites, the temperature equivalent of dipolar interactions is in the order of 1 K, much lower than that of direct exchange interactions and, hence, often mostly irrelevant to magnetic order such as ferromagnetism and antiferromagnetism.…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of dipole-induced exchange bias

Lü

Hu²

2020

Nanotechnology

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A modified Monte Carlo method is used to study the dependence of exchange bias, induced by long-range ferromagnet/antiferromagnet interfacial dipolar interactions, on temperature after field cooling. Since sufficient nonzero surplus magnetization in the antiferromagnetic layer is preserved, a positive exchange bias field is yielded. Significantly, this exchange field increases with decreasing temperature and may level off at low temperatures. Then, the antiferromagnetic anisotropy constant, easy-axis direction with respect to the cooling-field direction, antiferromagnetic exchange constant, and antiferromagnetic layer thickness were modulated to study their roles in establishing the low-temperature plateau-like exchange bias field. A thick enough antiferromagnetic layer with the easy-axis direction aligning with the cooling field maximizes the plateau height with a large antiferromagnetic anisotropy constant, while a small antiferromagnetic exchange constant greatly widens the plateau, even from the exchange bias blocking temperature to the lowest temperature. On explicitly calculating the surplus magnetization values in the antiferromagnetic layer meanwhile the dipolar and Zeeman energies in the antiferromagnetic layer, it is found that the ferromagnet/antiferromagnet interfacial dipolar interactions are predominant at the descending branch of the loop to suppress the coercive field with decreasing temperature; in contrast, the magnetic field takes over the lead at the ascending branch and monotonically enhances the coercive field, at the same pace as the decrease in the coercive field at the descending branch. As a consequence, the loop retains a constant shift and becomes wider with decreasing temperature. The long-range noncontact exchange bias that is insensitive to temperature may be used to develop thermal-agitation-resistant spintronic devices with unidirectional anisotropy.

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An extraordinary chiral exchange-bias phenomenon: engineering the sign of the bias field in orthogonal bilayers by a magnetically switchable response mechanism

Abstract: The competition between magnetic anisotropies in an exchange bias-like bilayer leads to a pinning mechanism, reported for the first time, going from negative to positive bias field through zero (no bias). The chirality of the effect is also proven.

Cited by 9 publications

References 42 publications

Measuring interfacial Dzyaloshinskii-Moriya interaction in ultra-thin magnetic films

Measuring interfacial Dzyaloshinskii-Moriya interaction in ultra-thin magnetic films

Comparison of stable spin textures in in-plane vs. out-of-plane magnetized exchange-biased multilayers

Temperature dependence of dipole-induced exchange bias

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