A new reversal mode in exchange coupled antiferromagnetic/ferromagnetic disks: distorted viscous vortex

Gilbert, Dustin A.; Li, Ye; Varea, A.; Agramunt-Puig, Sebastià; Valle, N.; Navau, Carles; López-Barberá, José Francisco; Buchanan, Kristen; Hoffmann, A.; Sánchez, Adrian A.; Sort, Jordi; Liu, Kai; Nogués, J.

doi:10.1039/c5nr01856k

Cited by 19 publications

(13 citation statements)

References 66 publications

(138 reference statements)

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“…Two types of uncompensated spins have been identified: pinned (unaffected by the magnetic field and which give rise to H E ) and unpinned or rotatable (which are dragged by the FM component and are related to the enhancement of HC). [59][60][61][62][63] In a hysteresis loop the pinned uncompensated spins are evidenced by a vertical shift. 50 Assuming that, once the FM magnetization is switched, the rotatable uncompensated spins can be further dragged by the applied magnetic field, then χHF should have a contribution from these uncompensated spins.…”

Section: Resultsmentioning

confidence: 99%

Maximizing Exchange Bias in Co/CoO Core/Shell Nanoparticles by Lattice Matching between the Shell and the Embedding Matrix

et al. 2017

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The exchange bias properties of 5 nm Co/CoO ferromagnetic/antiferromagnetic core/shell nanoparticles, highly dispersed in a CuxO matrix, have been optimized by matching the lattice parameter of the matrix with that of the CoO shell. Exchange bias and coercivity fields as large as HE = 7780 Oe and HC = 6950 Oe are linked to the presence of a Cu2O matrix (0.3% lattice mismatch with respect to the shells). The small mismatch between Cu2O and CoO plays a dual role, (i) structurally stabilizing the CoO and (ii) favoring the existence of a large amount of uncompensated moments in the shell that enhance the exchange bias effects. The results evidence that lattice matching may be a very efficient way to improve the exchange bias properties of core/shell nanoparticles, paving the way to novel approaches to tune their magnetic properties.

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Section: Resultsmentioning

confidence: 99%

Maximizing Exchange Bias in Co/CoO Core/Shell Nanoparticles by Lattice Matching between the Shell and the Embedding Matrix

et al. 2017

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“…Therefore, we focus on the current-driven skyrmion motion in this work. Here we show that the SkHE is completely suppressed by considering two perpendicularly magnetized ferromagnetic (FM) sublayers strongly coupled via the antiferromagnetic (AFM) exchange interaction with a heavy-metal layer beneath the bottom FM layer 33 34 ( Fig. 1a–c ).…”

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confidence: 86%

Magnetic bilayer-skyrmions without skyrmion Hall effect

Zhang¹,

Zhou²,

Ezawa³

2016

Nat Commun

473

401

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Magnetic skyrmions might be used as information carriers in future advanced memories, logic gates and computing devices. However, there exists an obstacle known as the skyrmion Hall effect (SkHE), that is, the skyrmion trajectories bend away from the driving current direction due to the Magnus force. Consequently, the skyrmions in constricted geometries may be destroyed by touching the sample edges. Here we theoretically propose that the SkHE can be suppressed in the antiferromagnetically exchange-coupled bilayer system, since the Magnus forces in the top and bottom layers are exactly cancelled. We show that such a pair of SkHE-free magnetic skyrmions can be nucleated and be driven by the current-induced torque. Our proposal provides a promising means to move magnetic skyrmions in a perfectly straight trajectory in ultra-dense devices with ultra-fast processing speed.

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“…The agreement with the experiment is quite good considering the simplifications of the model, which include zero temperature, periodic boundary conditions in only one direction, and the treatment of exchange bias as a fixed Zeeman field in the film. More realistic treatment of exchange bias, such as modeling the AF as a fraction of pinned and rotatable magnetic cells representing uncompensated moments [28], may produce better quantitative agreement with the experimental observations.…”

Section: A Exchange Bias Parallel To Gratingmentioning

confidence: 61%

Magnetization Reversal in Ferromagnetic Films Patterned with Antiferromagnetic Gratings of Various Sizes

Liu

Ross

2015

Phys. Rev. Applied

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The magnetic switching behavior in continuous NiFe films patterned with IrMn gratings is investigated experimentally and with micromagnetic simulations. The samples made by a two-step deposition process consist of a 10-nm-thick NiFe layer on which is placed 10-nm-thick IrMn stripes with width from 100 to 500 nm and period from 240 nm to 1 μm. Exchange bias is introduced by field cooling in directions parallel or perpendicular to the IrMn stripes. The samples display a two-step hysteresis loop for higher stripe width and period, as the pinned and unpinned regions of the NiFe reverse independently but a one-step loop for lower stripe periods. The transition between these regimes is reproduced by micromagnetic modeling.

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A new reversal mode in exchange coupled antiferromagnetic/ferromagnetic disks: distorted viscous vortex

Cited by 19 publications

References 66 publications

Maximizing Exchange Bias in Co/CoO Core/Shell Nanoparticles by Lattice Matching between the Shell and the Embedding Matrix

Maximizing Exchange Bias in Co/CoO Core/Shell Nanoparticles by Lattice Matching between the Shell and the Embedding Matrix

Magnetic bilayer-skyrmions without skyrmion Hall effect

Magnetization Reversal in Ferromagnetic Films Patterned with Antiferromagnetic Gratings of Various Sizes

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