Direct evidence of imprinted vortex states in the antiferromagnet of exchange biased microdisks

Salazar-Alvarez, Germán; Kavich, J. J.; Sort, Jordi; Mugarza, Aitor; Stepanow, Sebastian; Potenza, A.; Marchetto, Helder; Dhesi, S. S.; Baltz, Vincent; Diény, B.; Weber, A. P.; Heyderman, Laura J.; Nogués, J.; Gambardella, Pietro

doi:10.1063/1.3168515

Cited by 27 publications

(25 citation statements)

References 25 publications

(32 reference statements)

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“…Figure 12 shows curling and divergent vortices in the volume of antiferromagnetic NiO and CoO disks, as measured by x-ray magnetic linear dichroism (Wu et al, 2011). These data are complementary to circular dichroism observations of vortex states in IrMn layers (Salazar-Alvarez et al, 2009), where the signal was produced by the uncompensated moments at the IrMn interface rather than from the moments in the volume of the antiferromagnet. In both experiments, the vortex was imprinted from a ferromagnet into the antiferromagnet via exchange-bias interactions (Sec.…”

Section: A Experimental Observation Of Antiferromagnetic Texturesmentioning

confidence: 60%

“…III.B). Finally, imprinting multidomain states and magnetic textures in antiferromagnets can be achieved by preparing the ferromagnet in specific magnetic configurations, e.g., multidomain (Brück et al, 2005;Roshchin et al, 2005) and vortex (Salazar-Alvarez et al, 2009;Wu et al, 2011) states. Section I.C.4 is devoted to antiferromagnetic textures.…”

Section: Manipulation By Exchange Biasmentioning

confidence: 99%

“…Direct observation usually requires large scale facilities with element-sensitive techniques like x-ray absorption spectroscopy (Weber et al, 2003;Salazar-Alvarez et al, 2009;Wu et al, 2011) or specific techniques with local probes like spin-polarized scanning tunneling microscopy (Bode et al, 2006;Loth et al, 2012) and quantum sensing with single spins (nitrogen vacancies) in diamond (Gross et al, 2017;Kosub et al, 2017). Alternatively, some information about antiferromagnetic domains can be inferred using indirect transport measurements.…”

Section: A Experimental Observation Of Antiferromagnetic Texturesmentioning

confidence: 99%

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Antiferromagnetic spintronics

et al. 2018

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Antiferromagnetic materials could represent the future of spintronic applications thanks to the numerous interesting features they combine: they are robust against perturbation due to magnetic fields, produce no stray fields, display ultrafast dynamics, and are capable of generating large magnetotransport effects. Intense research efforts over the past decade have been invested in unraveling spin transport properties in antiferromagnetic materials. Whether spin transport can be used to drive the antiferromagnetic order and how subsequent variations can be detected are some of the thrilling challenges currently being addressed. Antiferromagnetic spintronics started out with studies on spin transfer and has undergone a definite revival in the last few years with the publication of pioneering articles on the use of spin-orbit interactions in antiferromagnets. This paradigm shift offers possibilities for radically new concepts for spin manipulation in electronics. Central to these endeavors are the need for predictive models, relevant disruptive materials, and new experimental designs. This paper reviews the most prominent spintronic effects described based on theoretical and experimental analysis of antiferromagnetic materials. It also details some of the remaining bottlenecks and suggests possible avenues for future research. This review covers both spin-transfer-related effects, such as spin-transfer torque, spin penetration length, domain-wall motion, and "magnetization" dynamics, and spin-orbit related phenomena, such as (tunnel) anisotropic magnetoresistance, spin Hall, and inverse spin galvanic effects. Effects related to spin caloritronics, such as the spin Seebeck effect, are linked to the transport of magnons in antiferromagnets. The propagation of spin waves and spin superfluids in antiferromagnets is also covered.

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Section: A Experimental Observation Of Antiferromagnetic Texturesmentioning

confidence: 60%

Section: Manipulation By Exchange Biasmentioning

confidence: 99%

Section: A Experimental Observation Of Antiferromagnetic Texturesmentioning

confidence: 99%

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Antiferromagnetic spintronics

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“…The conjecture of antiparallel coupling at the IrMn/NiFe interface agrees with works on the same system. 6,39 Experiments 40 and calculations 41 have established the antiparallel Fe-Mn configuration for small surface coverage of Mn atoms. It has also been claimed that at IrMn/CoFeB interfaces uncompensated Mn spins can couple antiferromagnetically to the FM spins resulting in PEB.…”

Section: Resultsmentioning

confidence: 98%

Antiparallel interface coupling evidenced by negative rotatable anisotropy in IrMn/NiFe bilayers

Schafer

Grande

Pereira

et al. 2015

Journal of Applied Physics

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Negative rotatable anisotropy is estimated via ferromagnetic resonance measurements in as-made, annealed, and ion-irradiated IrMn 3 /Ni 81 Fe 19 bilayers. Opposite to previous observations, inverse correlation between rotatable anisotropy and coercivity is observed. The exchange-bias field, determined from hysteresis loop measurements, is higher than that obtained from ferromagnetic resonance for all samples. The results are discussed in terms of majority antiparallel coupling and magnetic-field-induced transitions from antiparallel to parallel states of uncompensated spins at ferromagnet/antiferromagnet interface. We affirm that an observation of negative rotatable anisotropy evidences antiparallel coupling even in systems presenting conventional exchange bias. V C 2015 AIP Publishing LLC. [http://dx

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“…[64][65][66] Pulse electrodeposition offers an additional advantage with respect to electrodeposition at a constant potential. Namely, during potentiostatic electrodeposition, hydrogen evolves continuously and could eventually block the central part of the pores, thus shielding the deposition from the pore center.…”

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confidence: 99%

Tunable High-Field Magnetization in Strongly Exchange-Coupled Freestanding Co/CoO Core/Shell Coaxial Nanowires

Salazar-Alvarez

Geshev

Agramunt-Puig

et al. 2016

ACS Appl. Mater. Interfaces

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The exchange bias properties of Co/CoO coaxial core/shell nanowires have been investigated with cooling and applied fields perpendicular to the wire axis. This configuration leads to unexpected exchange-bias effects. Firstly, the magnetization value at high fields is found to depend on the field-cooling conditions. This effect arises from the competition between the magnetic anisotropy and the Zeeman energies for cooling fields perpendicular to the wire axis. This allows imprinting pre-defined magnetization states to the AFM, as corroborated by micromagnetic simulations. Secondly, the system exhibits a high-field magnetic irreversibility, leading to open hysteresis loops, attributed to the AFM easy-axis reorientation during the reversal (effect similar to athermal training). A distinct way to manipulate the high-field magnetization in exchange-biased systems, beyond the archetypical effects, is thus experimentally and theoretically demonstrated.

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Direct evidence of imprinted vortex states in the antiferromagnet of exchange biased microdisks

Cited by 27 publications

References 25 publications

Antiferromagnetic spintronics

Antiferromagnetic spintronics

Antiparallel interface coupling evidenced by negative rotatable anisotropy in IrMn/NiFe bilayers

Tunable High-Field Magnetization in Strongly Exchange-Coupled Freestanding Co/CoO Core/Shell Coaxial Nanowires

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