Thickness dependence of ferrimagnetic compensation in amorphous rare-earth transition-metal thin films

Ting, Chung; Kirby, Brian J.; Li, Xiaopu; Poon, S. J.

doi:10.1063/1.5050626

Cited by 12 publications

(4 citation statements)

References 38 publications

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“…Analysis of the PNR data revealed that both top and bottom mixing layers exhibit essentially zero magnetization. The 5 nm thickness of the mixed layer at the MgO/Mn 4 N interface is comparable to other room temperature depositions 19,20 , despite Mn 4 N being deposited at 450 • C. Equally important, micromagnetic simulations presented herein show that even with the presence of mixing layers, magnetic skyrmions, which arise from I-DMI, are found to be stable in MgO/Mn 4 N/Pt x Cu 1−x thin films. This finding is consistent with recent experimental results.…”

Section: Introductionsupporting

confidence: 77%

“…Furthermore, it has been reported that in many of these heterostructures, interfacial mixing and dead layers exist at the interfaces of magnetic and non-magnetic layers. Such interfacial compositional heterogeneities have led to varying magnetic properties, such as thickness-dependent anisotropy and magnetization [15][16][17][18][19][20][21] . These present challenges in fabricating and developing devices with magnetic thin films, such as magnetic tunnel junctions 22 .…”

Section: Introductionmentioning

confidence: 99%

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Interfacial Mixing Effect in a Promising Skyrmionic Material: Ferrimagnetic Mn$_4$N

Ma¹,

Zhou²,

Kirby³

et al. 2022

Preprint

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Section: Introductionsupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Interfacial Mixing Effect in a Promising Skyrmionic Material: Ferrimagnetic Mn$_4$N

Ma¹,

Zhou²,

Kirby³

et al. 2022

Preprint

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“…an infinitely thick film). This indicates that there is a residual DMI of 0.025 mJ m −2 , which may result from a change of the magnetization compensation temperature throughout the thickness as evidenced in another rare-earth transition-metal alloy 43 that could induce inversion symmetry breaking. Yet, as the thickness decreases, the interfacial effects become more important and the DMI increases as seen in Fig.…”

Section: Resultsmentioning

confidence: 95%

Tuning interfacial Dzyaloshinskii-Moriya interactions in thin amorphous ferrimagnetic alloys

Quessab¹,

Xu²,

T.³

et al. 2020

Sci Rep

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Skyrmions can be stabilized in magnetic systems with broken inversion symmetry and chiral interactions, such as Dzyaloshinskii-Moriya interactions (DMi). further, compensation of magnetic moments in ferrimagnetic materials can significantly reduce magnetic dipolar interactions, which tend to favor large skyrmions. tuning DMi is essential to control skyrmion properties, with symmetry breaking at interfaces offering the greatest flexibility. However, in contrast to the ferromagnet case, few studies have investigated interfacial DMi in ferrimagnets. Here we present a systematic study of DMI in ferrimagnetic CoGd films by Brillouin light scattering. We demonstrate the ability to control DMI by the coGd cap layer composition, the stack symmetry and the ferrimagnetic layer thickness. the DMi thickness dependence confirms its interfacial nature. In addition, magnetic force microscopy reveals the ability to tune DMI in a range that stabilizes sub-100 nm skyrmions at room temperature in zero field. our work opens new paths for controlling interfacial DMi in ferrimagnets to nucleate and manipulate skyrmions. Magnetic skyrmions due to their non-trivial topology have interesting properties 1-3 that make them attractive for spintronic applications, such as racetrack memory and logic devices 4-6. A magnetic skyrmion designates a chiral spin texture with a whirling spin configuration 7. Skyrmions can be stabilized by broken inversion symmetry and chiral interactions, such as the Dzyaloshinskii-Moriya interactions (DMI) 8,9 , which is an antisymmetric exchange interaction that favors non-collinear neighboring spins. Ultrathin magnetic materials with interfaces to heavy non-magnetic metals with large spin-orbit coupling exhibit interfacial DMI that stabilizes skyrmions and chiral domain walls 10-13. The interfacial DMI and the nucleation of skyrmions have been extensively investigated in ferromagnetic materials 10,14-18. Very recently, magnetic skyrmions and chiral domains were reported in ferrimagnetic systems 19-21. Nearly compensated thin ferrimagnetic films with interfacial DMI are interesting materials due to their low stray fields, reduced sensitivity to external magnetic fields, and fast spin dynamics, which are predicted to lead to ultrasmall and ultrafast skyrmions 19,22. Unlike in ferromagnets where fast current-induced motion of chiral textures is impeded by the Walker breakdown and domain wall pinning 13,23-25 , high domain wall velocities-reaching 1000 m s-1-have been observed in ferrimagnetic CoGd films near the angular momentum compensation temperature 19. In addition, the large dipolar fields in ferromagnets are obstacles to the formation of ultrasmall skyrmion 22. Hence, ferrimagnetic thin films are promising candidates for ultrafast skyrmion-based spintronics. Recently, bulk DMI was reported in an amorphous ferrimagnetic GdFeCo alloy 26. However, the significant advantages of interfacial DMI are that it can be controlled by the nature of the interfaces and widely tuned to stabilize skyrmions. Yet, interfacial DM...

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“…Compared to SAF with ferromagnet or multilayer RE/TM films, SAF with RE-TM allows more flexible tuning of each layer. The thickness 34 , 35 and composition 23 of each layer can be varied while the net magnetization stays zero, and PMA remains robust. In contrast, SAF with ferromagnet and multilayer RE-TM films are limited in thickness and composition to maintain PMA 18 , 36 .…”

Section: Introductionmentioning

confidence: 99%

Ultrafast switching in synthetic antiferromagnet with bilayer rare-earth transition-metal ferrimagnets

Ting

Zhou

Poon

2022

Sci Rep

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In spintronics, it is important to be able to manipulate magnetization rapidly and reliably. Several methods can control magnetization, such as by applying current pulses or magnetic fields. An applied current can reverse magnetization with nanosecond speed through the spin torque effect. For faster switching, subpicosecond switching with femtoseconds laser pulse has been achieved in amorphous rare-earth transition-metal ferrimagnets. In this study, we employed atomistic simulations to investigate ultrafast switching in a synthetic antiferromagnet with bilayer amorphous FeGd ferrimagnets. Using a two-temperature model, we demonstrated ultrafast switching in this synthetic antiferromagnet without external magnetic fields. Furthermore, we showed that if we initially stabilize a skyrmion in this heterostructure, the ultrafast laser can switch the skyrmion state using the same mechanism. Furthermore, this bilayer design allows the control of each ferrimagnetic layer individually and opens the possibility for a magnetic tunnel junction.

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Thickness dependence of ferrimagnetic compensation in amorphous rare-earth transition-metal thin films

Cited by 12 publications

References 38 publications

Interfacial Mixing Effect in a Promising Skyrmionic Material: Ferrimagnetic Mn$_4$N

Interfacial Mixing Effect in a Promising Skyrmionic Material: Ferrimagnetic Mn$_4$N

Tuning interfacial Dzyaloshinskii-Moriya interactions in thin amorphous ferrimagnetic alloys

Ultrafast switching in synthetic antiferromagnet with bilayer rare-earth transition-metal ferrimagnets

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