Robust picosecond writing of a layered antiferromagnet by staggered spin-orbit fields

Roy, P. E.; Otxoa, R. M.; Wunderlich, J.

doi:10.1103/physrevb.94.014439

Cited by 65 publications

(60 citation statements)

References 29 publications

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“…Interest in antiferromagnets has been recently renewed in part due to progress in the theoretical understanding of their interaction with electric currents [1][2][3][4] that culminated in the experimental demonstration of the electrical switching of CuMnAs [5] and the consequent prospect of future applications. Apart from being more ubiquitous in Nature than ferromagnets, antiferromagnets enjoy attractive properties: lack of stray fields, insensitiveness to external magnetic field perturbations, and ultrafast dynamics in the THz range [6][7][8][9]. Moreover, spintronics research on antiferromagnets has led to the study of spin currents carried by magnetic excitations [10][11][12][13][14][15].…”

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confidence: 99%

Topological Magnons and Edge States in Antiferromagnetic Skyrmion Crystals

2019

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Antiferromagnetic skyrmion crystals are magnetic phases predicted to exist in antiferromagnets with Dzyaloshinskii-Moriya interactions. Their spatially periodic noncollinear magnetic texture gives rise to topological bulk magnon bands characterized by nonzero Chern numbers. We find topologically-protected chiral magnonic edge states over a wide range of magnetic fields and Dzyaloshinskii-Moriya interaction values. Moreover, and of particular importance for experimental realizations, edge states appear at the lowest possible energies, namely, within the first bulk magnon gap. Thus, antiferromagnetic skyrmion crystals show great promise as novel platforms for topological magnonics.

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confidence: 99%

Topological Magnons and Edge States in Antiferromagnetic Skyrmion Crystals

2019

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“…Secondly, if the antiferromagnetic sublattices are space-inversion partners, the currentinduced spin polarization generates an effective magnetic field (H eff ) whose sign alternates with each sublattice. This staggered field can induce a Néel-order spin-orbit torque (NSOT) 6 important role as it determines the DW propagation direction 11,12 . This is illustrated in Fig.…”

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“…Then, there is a torque acting on the wall whose sign depends on the polarity of I pulse . Moreover, the strong intersublattice exchange coupling in an antiferromagnet is predicted to result in much faster DW motion compared to ferromagnets, where the velocity is limited by Walker breakdown 11,12,14,15 . Figures 1b-d show an optical micrograph and antiferromagnetic domain images for a 10m cross structure fabricated from a 45nm thick CuMnAs film.…”

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confidence: 99%

Current polarity-dependent manipulation of antiferromagnetic domains

et al. 2018

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Antiferromagnets have several favourable properties as active elements in spintronic devices, including ultra-fast dynamics, zero stray fields and insensitivity to external magnetic fields . Tetragonal CuMnAs is a testbed system in which the antiferromagnetic order parameter can be switched reversibly at ambient conditions using electrical currents . In previous experiments, orthogonal in-plane current pulses were used to induce 90° rotations of antiferromagnetic domains and demonstrate the operation of all-electrical memory bits in a multi-terminal geometry . Here, we demonstrate that antiferromagnetic domain walls can be manipulated to realize stable and reproducible domain changes using only two electrical contacts. This is achieved by using the polarity of the current to switch the sign of the current-induced effective field acting on the antiferromagnetic sublattices. The resulting reversible domain and domain wall reconfigurations are imaged using X-ray magnetic linear dichroism microscopy, and can also be detected electrically. Switching by domain-wall motion can occur at much lower current densities than those needed for coherent domain switching.

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“…AFMs offer some unique advantages compared to FMs, but are much less explored (see reviews [11][12][13]). AFMs have a very fast dynamics, which allows for switching on ps timescale [14][15][16]. Furthermore, there exists a wide range of AFM materials, including many insulators and semiconductors, multiferroics [17] and superconductors [18].…”

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Spin-Polarized Current in Noncollinear Antiferromagnets

et al. 2017

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Noncollinear antiferromagnets, such as Mn3Sn and Mn3Ir, were recently shown to be analogous to ferromagnets in that they have a large anomalous Hall effect. Here we show that these materials are similar to ferromagnets in another aspect: the charge current in these materials is spin-polarized. In addition, we show that the same mechanism that leads to the spin-polarized current also leads to a transversal spin current, which has a distinct symmetry and origin from the conventional spin Hall effect. We illustrate the existence of the spin-polarized current and the transversal spin current by performing ab initio microscopic calculations and by analyzing the symmetry. Based on the spinpolarized current we propose an antiferromagnetic tunneling junction, analogous in functionality to the magnetic tunneling junction.Introduction. Spintronics is a field that studies phenomena in which both spin and charge degree of electron play an important role. Many of the key spintronics effects are based upon the existence of spin currents. Two main types of spin currents are utilized: the spin-polarized currents in ferromagnets (FMs) and the spin currents due to the spin Hall effect (SHE) which are transveral to the charge current and appear even in non-magnetic materials. The most important effects that originate from the spin-polarized currents in FMs are the giant and the tunneling magnetoresistance effects (GMR and TMR) [1][2][3] and the spin-transfer torque (STT) [4,5]. These effects are utilized in magnetic tunneling junctions (MTJs), which form the basic building block of a new type of solid state memory, the magnetic random access memory (MRAM) [6]. This memory is non-volatite and has speed and density comparable to the widely used dynamic random access memory. The SHE on the other hand is responsible (though other effects can contribute) for the spin-orbit torque (SOT) [7,8] in multilayer heterostructures, which can be used for efficient and fast switching of FM layers. The SOT is now also being explored for use in MRAMs [9,10].While spintronics has traditionally focused on FM and non-magnetic materials, in the past few years also antiferromagnetic (AFM) materials have attracted a considerable interest. AFMs offer some unique advantages compared to FMs, but are much less explored (see reviews [11][12][13]). AFMs have a very fast dynamics, which allows for switching on ps timescale [14][15][16]. Furthermore, there exists a wide range of AFM materials, including many insulators and semiconductors, multiferroics [17] and superconductors [18]. Utilizing (and also studying) AFMs is difficult, largely because the magnetic order in AFMs is hard to detect and to manipulate. Recently, electrical detection [19][20][21][22][23] and manipulation of the AFM order has been demonstrated [23,24], however, both detection and manipulation still remain challenging from a practical point of view.

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Robust picosecond writing of a layered antiferromagnet by staggered spin-orbit fields

Cited by 65 publications

References 29 publications

Topological Magnons and Edge States in Antiferromagnetic Skyrmion Crystals

Topological Magnons and Edge States in Antiferromagnetic Skyrmion Crystals

Current polarity-dependent manipulation of antiferromagnetic domains

Spin-Polarized Current in Noncollinear Antiferromagnets

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