Electrical Measurement of Antiferromagnetic Moments in Exchange-Coupled<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>IrMn</mml:mi><mml:mo>/</mml:mo><mml:mi>NiFe</mml:mi></mml:math>Stacks

Martí, X.; Park, Byong‐Guk; Wunderlich, J.; Reichlová, Helena; Kurosaki, Yosuke; Yamada, Masaki; Yamamoto, Hirotsugu; Nishide, Akemi; Hayakawa, Jun; Takahashi, Hirokazu; Jungwirth, T.

doi:10.1103/physrevlett.108.017201

Cited by 73 publications

(73 citation statements)

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“…The exchange bias and broadening of the Fe hysteresis loop induced by CuMnAs provides not only additional evidence for the high-temperature AFM ordering in the tetragonal CuMnAs epilayers, but also clearly demonstrates the potential of this new material for AFM-based spintronic functionalization. The same type of AFM/FM exchange-coupling phenomena was utilized in the demonstration of the first AFMtunnelling anisotropic magnetoresistance devices 1,2,6 .…”

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confidence: 99%

“…L arge and bistable magnetoresistance signals have been observed in tunnelling devices with an antiferromagnetic (AFM) IrMn layer on one side and a non-magnetic metal on the other side of the tunnel barrier 1,2 . The work has experimentally demonstrated the feasibility of a spintronic concept [3][4][5] in which the electronic device characteristics are governed by the staggered magnetization axis in an AFM.…”

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confidence: 99%

“…The work has experimentally demonstrated the feasibility of a spintronic concept [3][4][5] in which the electronic device characteristics are governed by the staggered magnetization axis in an AFM. It has been shown that the AFM moments can be manipulated via an exchange-coupled ferromagnet (FM) 1,2,6 and that the AFM magnetoresistance signals can persist to room temperature 6 . No stray fields and the relative insensitivity to external magnetic fields are among the features that make AFMs attractive complements to the conventionally utilized FMs in the design of spintronic devices, as highlighted in a recent study of AFM linear chains of a few Fe atoms 7 and in the demonstration of the concept of an AFM memory 8 .…”

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Tetragonal phase of epitaxial room-temperature antiferromagnet CuMnAs

et al. 2013

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Recent studies have demonstrated the potential of antiferromagnets as the active component in spintronic devices. This is in contrast to their current passive role as pinning layers in hard disk read heads and magnetic memories. Here we report the epitaxial growth of a new hightemperature antiferromagnetic material, tetragonal CuMnAs, which exhibits excellent crystal quality, chemical order and compatibility with existing semiconductor technologies. We demonstrate its growth on the III-V semiconductors GaAs and GaP, and show that the structure is also lattice matched to Si. Neutron diffraction shows collinear antiferromagnetic order with a high Néel temperature. Combined with our demonstration of room-temperatureexchange coupling in a CuMnAs/Fe bilayer, we conclude that tetragonal CuMnAs films are suitable candidate materials for antiferromagnetic spintronics.

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Tetragonal phase of epitaxial room-temperature antiferromagnet CuMnAs

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“…There are no stray fields in antiferromagnets, making them more robust against the influence of external magnetic fields. The recent discovery of anisotropic magnetoresistance [15][16][17], spin-orbit torques [18], and electrical switching of an antiferromagnet [19] demonstrate the feasibility of antiferromagnets as active spintronics components.The real benefit of antiferromagnets is that they can enable terahertz circuits. Unlike ferromagnets, the resonance frequency of antiferromagnets is also governed by the tremendous exchange energy.…”

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Spin pumping and inverse spin Hall voltages from dynamical antiferromagnets

Johansen

Brataas

2017

Phys. Rev. B

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Dynamical antiferromagnets can pump spins into adjacent conductors. The high antiferromagnetic resonance frequencies represent a challenge for experimental detection, but magnetic fields can reduce these resonance frequencies. We compute the ac and dc inverse spin Hall voltages resulting from dynamical spin excitations as a function of a magnetic field along the easy axis and the polarization of the driving ac magnetic field perpendicular to the easy axis. We consider the insulating antiferromagnets MnF 2 , FeF 2 , and NiO. Near the spin-flop transition, there is a significant enhancement of the dc spin pumping and inverse spin Hall voltage for the uniaxial antiferromagnets MnF 2 and FeF 2 . In the uniaxial antiferromagnets it is also found that the ac spin pumping is independent of the external magnetic field when the driving field has the optimal circular polarization. In the biaxial NiO, the voltages are much weaker, and there is no spin-flop enhancement of the dc component. DOI: 10.1103/PhysRevB.95.220408 Spin pumping is a versatile tool for probing spin dynamics in ferromagnets [1][2][3][4][5][6]. The magnitude of the pumped spin currents reveals information about the magnetization dynamics and the electron-magnon coupling at interfaces [7][8][9]. The precessing spins generate a pure spin flow into adjacent conductors. Inside the conductor, the resulting spin accumulation and currents give insight into the spin-orbit coupling. The inverse spin Hall effect (ISHE) is often used to convert the pure spin current into a charge current, which is detected [10,11]. Additionally, the induced nonequilibrium spins can be probed with x-ray magnetic circular dichroism measurements [12,13].Antiferromagnets differ strikingly from ferromagnets [14]. There are no stray fields in antiferromagnets, making them more robust against the influence of external magnetic fields. The recent discovery of anisotropic magnetoresistance [15][16][17], spin-orbit torques [18], and electrical switching of an antiferromagnet [19] demonstrate the feasibility of antiferromagnets as active spintronics components.The real benefit of antiferromagnets is that they can enable terahertz circuits. Unlike ferromagnets, the resonance frequency of antiferromagnets is also governed by the tremendous exchange energy. We recently demonstrated that the transverse spin conductance, a governing factor of spin pumping, is as large in antiferromagnet-normal metal junctions (AF|N) as in ferromagnet-normal metal junctions [20]. Furthermore, this result is valid even when the magnetic system is insulating. The firm electron-magnon coupling at the interface opens the door for electrical probing of the ultrafast spin dynamics in antiferromagnets [20,21].Precessing spins in antiferromagnets generate terahertz currents in adjacent conductors. This ability opens new territory in high-frequency spintronics. Such studies could become influential in gathering vital insight into fast electron dynamics and eventually for a broad range of applications. These electric sign...

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“…One of the milestones of AFM spintronics is finding an efficient method for monitoring the magneticorder parameter in AFM materials. Anisotropic magnetoresistance (AMR) [6] and tunneling AMR [7,8] observed in AFMs are among very promising candidates for this purpose. The canted AFM iridate Sr 2 IrO 4 (see Fig.…”

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Anisotropic Magnetoresistance in AntiferromagneticSr2IrO4

et al. 2014

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We report point-contact measurements of anisotropic magnetoresistance (AMR) in a single crystal of antiferromagnetic Mott insulator Sr 2 IrO 4 . The point-contact technique is used here as a local probe of magnetotransport properties on the nanoscale. The measurements at liquid nitrogen temperature reveal negative magnetoresistances (up to 28%) for modest magnetic fields (250 mT) applied within the IrO 2 a-b plane and electric currents flowing perpendicular to the plane. The angular dependence of magnetoresistance shows a crossover from fourfold to twofold symmetry in response to an increasing magnetic field with angular variations in resistance from 1% to 14%. We tentatively attribute the fourfold symmetry to the crystalline component of AMR and the field-induced transition to the effects of applied field on the canting of antiferromagnetic-coupled moments in Sr 2 IrO 4 . The observed AMR is very large compared to the crystalline AMRs in 3d transition metal alloys or oxides (0.1%-0.5%) and can be associated with the large spin-orbit interactions in this 5d oxide while the transition provides evidence of correlations between electronic transport, magnetic order, and orbital states. The finding of this work opens an entirely new avenue to not only gain a new insight into physics associated with spin-orbit coupling but also to better harness the power of spintronics in a more technically favorable fashion. [13] behaviors, which makes them an attractive playground for studying physics driven by spin-orbit interactions. As AMR is known to be closely associated with spin-orbit interaction, the strong spin-orbit interaction in this 5d transition metal oxide may favor stronger AMR compared to 3d transition metal alloys and oxides. The recent magnetotransport studies in Sr 2 IrO 4 single crystals [14,15] and thin films [6] revealed largely unexplored correlations between electronic transport, magnetic order, and orbital states.Here, we present the first observation of the pointcontact AMR in single crystals of the AFM Mott insulator Sr 2 IrO 4 [14-16], which can potentially be used to sense the AFM order parameter in spintronic nanodevices. The pointcontact technique allows us to probe very small volumes and, therefore, measures electronic transport on a microscopic scale. Point-contact measurements with single crystals of Sr 2 IrO 4 are intended to examine whether the additional local resistance associated with a small contact area between a sharpened Cu tip and the antiferromagnet shows a magnetoresistance (MR) like that seen in bulk crystals. The measurements at liquid nitrogen temperature reveal large MRs (up to 28%) for modest magnetic fields (250 mT) applied within the IrO 2 a-b plane. The angular dependence of MR reveals an AMR with an intriguing transition from fourfold to twofold symmetry in response to

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Electrical Measurement of Antiferromagnetic Moments in Exchange-CoupledIrMn/NiFeStacks

Cited by 73 publications

References 24 publications

Tetragonal phase of epitaxial room-temperature antiferromagnet CuMnAs

Tetragonal phase of epitaxial room-temperature antiferromagnet CuMnAs

Spin pumping and inverse spin Hall voltages from dynamical antiferromagnets

Anisotropic Magnetoresistance in AntiferromagneticSr2IrO4

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