Domain wall depinning governed by the spin Hall effect

Haazen, Ppj; Murè, E.; Franken, JH Jeroen; Lavrijsen, Reinoud; Swagten, Hjm Henk; Koopmans, B.

doi:10.1038/nmat3553

Cited by 527 publications

(520 citation statements)

References 28 publications

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“…motion [8][9][10] in recent experiments. Typical heterostructures exhibiting SOTs consist of a ferromagnet (F) with a heavy nonmagnetic metal (NM) having strong spin-orbit coupling on one side, and an insulator (I) on the other side (referred to as NM/F/I structures, shown schematically in Fig.…”

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confidence: 90%

“…The structural asymmetry in various magnetic heterostructures has been engineered to reveal novel fundamental interactions between electric currents and magnetization, resulting in spin-orbit-torques (SOTs) on the magnetization [1][2][3][4][5][6] , which are both fundamentally important and technologically promising for device applications. Such SOTs have been used to realize current-induced magnetization switching [2][3][4]7 and domain-wall 3 motion [8][9][10] in recent experiments. Typical heterostructures exhibiting SOTs consist of a ferromagnet (F) with a heavy nonmagnetic metal (NM) having strong spin-orbit coupling on one side, and an insulator (I) on the other side (referred to as NM/F/I structures, shown schematically in Fig.…”

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confidence: 99%

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Switching of perpendicular magnetization by spin–orbit torques in the absence of external magnetic fields

et al. 2014

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Breaking of structural symmetries of nanomagnetic systems is of great interest for the development of ultralow-power spintronic devices. The structural asymmetry in various magnetic heterostructures has been engineered to reveal novel fundamental interactions between electric currents and magnetization, resulting in spin-orbit-torques (SOTs) on the magnetization [1][2][3][4][5][6] , which are both fundamentally important and technologically promising for device applications. Such SOTs have been used to realize current-induced magnetization switching [2][3][4]7 and domain-wall 3 motion [8][9][10] in recent experiments. Typical heterostructures exhibiting SOTs consist of a ferromagnet (F) with a heavy nonmagnetic metal (NM) having strong spin-orbit coupling on one side, and an insulator (I) on the other side (referred to as NM/F/I structures, shown schematically in Fig. 1a, which break mirror symmetry in the growth direction). In terms of device applications, the use of SOTs in NM/F/I structures allows for a significantly lower write current compared to regular spin-transfer-torque (STT) devices 4 . It can greatly improve energy efficiency and scalability [1][2][3][4][5]11 for new SOT-based devices such as magnetic random access memory (SOT-MRAM), going beyond state-of-the-art STT-MRAM.For practical applications, a critical requirement to achieve high-density SOT memory is the ability to perform SOT-induced switching without the use of external magnetic fields, in particular for perpendicularly-magnetized ferromagnets, which show better scalability and thermal stability as compared to the in-plane case 12 .However, there are currently no practical solutions that meet this requirement. In NM/F/I heterostructures studied so far, the form of the resultant current-induced SOT alone does not allow for deterministic switching of a perpendicular ferromagnet, requiring application of an additional external in-plane magnetic field to switch the perpendicular magnetization [2][3][4] . (This is a very general feature of SOT devices, which can be explained by symmetry-based arguments, as discussed below). In such experiments, the external field allows for each current direction to favor a particular orientation for the out-of-plane component of magnetization, thereby resulting in deterministic perpendicular switching. However, this external field is undesirable 4 from a practical point of view. For device applications, it also reduces the thermal stability of the perpendicular magnet by lowering the zero-current energy barrier between the stable perpendicular states, resulting in a shorter retention time if used for memory.This work provides a solution to eliminate the use of external magnetic fields, bringing SOT-based spintronic devices such as SOT-MRAM closer to practical application. We present a new NM/F/I structure, which provides a novel spin-orbit torque, resulting in zero-field current-induced switching of perpendicular magnetization. Our device consists of a stack of Ta/Co 20 Fe 60 B 20 /TaO x layers, but also has a...

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Switching of perpendicular magnetization by spin–orbit torques in the absence of external magnetic fields

et al. 2014

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“…This makes them attractive for spintronics applications, such as torque-induced magnetization control in nanodevices [1][2][3], for sensing, data storage, interconnects, and logics. Up to now, however, most spin transfer torque studies focused on metallic ferromagnets [4][5][6][7][8], while magnetic insulators received much less attention [9][10][11]. However, some magnetic insulators such as yttrium iron garnet (YIG) with extremely low magnetization damping [12] are well suited for the long-range transmission of signals via magnetization dynamics, and may harbor magnon condensates [13] or magnonic crystals [14].…”

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confidence: 99%

Current-induced spin torque resonance of a magnetic insulator

et al. 2015

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We report the observation of current-induced spin torque resonance in yttrium iron garnet/platinum bilayers. An alternating charge current at GHz frequencies in the platinum gives rise to dc spin pumping and spin Hall magnetoresistance rectification voltages, induced by the Oersted fields of the ac current and the spin Hall effect-mediated spin transfer torque. In ultrathin yttrium iron garnet films, we observe spin transfer torque actuated magnetization dynamics which are significantly larger than those generated by the ac Oersted field. Spin transfer torques thus efficiently couple charge currents and magnetization dynamics also in magnetic insulators, enabling charge current-based interfacing of magnetic insulators with microwave devices.

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“…The spin Hall effect (SHE) [1][2][3], in which a transverse spin current density SHE j is induced by a longitudinal charge current density e j and whose strength is characterized by the spin Hall ratio SH SHE (2 / ) / e e j j θ ≡ h , has recently drawn much attention because of its promise for spintronics applications [4][5][6][7][8][9][10][11][12][13]. Mechanisms which might give rise to the SHE [14,15] include the intrinsic SHE [1,16], side-jump scattering [17] and skew scattering [18].…”

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confidence: 99%