Spin-orbit torque (SOT)-Electrical manipulation of magnetization allows us to realize low-power and high-performance solid-state devices. Recent studies have revealed that an in-plane electric current applied to a heterostructure with large spin-orbit interaction and structural inversion asymmetry gives rise to a torque, so-called SOT, which in turn induces a magnetization switching [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] . The SOT-induced switching is useful for three-terminal spintronics device that is capable of high-speed and reliable operation 19 . The origin of SOT is considered to arise from the bulk spin Hall effect (SHE) in the NM and/or the heterostructure interface(s). According to the scenario attributed to the SHE, the in-plane current flowing in the NM generates a pure spin current in the orthogonal direction that is manifested in a Slonczewski-like torque and a field-like torque acting upon the magnetization of FM 5,8,9 , where the ratio of the spin current to the charge current is represented by the spin Hall angle. Among the two magnetic configurations presented so far, the perpendicular one has an advantage in terms of fast switching 11,16 and scalability; however, the requirement of a static magnetic field being applied collinear with the current to achieve bipolar switching poses a technological challenge. While recent studies have shown that the need for the field can be eliminated by introducing a lateral structural asymmetry 14,15,17 , the present work addresses this issue by employing a new material system. 23,24 . These works promise the existence of a direct SHE in AFM that eventually generates SOT. Note that the AFM can exert an internal effective field on the adjacent FM through the exchange-bias [25][26][27] , which has been a core technology for the read heads of the hard-disk drives. Therefore, by replacing the NM by the AFM, external-field-free switching of perpendicular magnetization may be possible in the AFM/FM bilayer systems through the SOT arising from the direct SHE in the AFM.Here we study the SOT switching in an AFM/FM bilayer system. We develop stacks consisting of an in-plane exchange-biased ferromagnetic Co/Ni multilayer with a perpendicular easy axis on top of an antiferromagnetic PtMn (Fig. 1a). Evidence of direct SHE and resulting SOT-induced switching under zero magnetic fields are obtained. Furthermore, we find that, in the AFM/FM system, the portion of reversed magnetization can be controlled continuously by adjusting the magnitude of the applied current; in other words, the system has the potential to serve as a memristor [28][29][30][31] , which is useful for neuromorphic computing 32 . samples. For t PtMn = 6.0 nm (non-biased device), the diagram shows fourfold symmetry, that is, the variation of H C depends on neither the switching direction nor the sign of I CH ; on the other hand, for t PtMn = 8.0 nm (exchange-biased device), it shows twofold symmetry, that is, the sign of I CH specifies the preferable switching direction. We ...

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Efficient information processing in the human brain is achieved by dynamics of neurons and synapses, motivating effective implementation of artificial spiking neural networks. Here, the dynamics of spin–orbit torque switching in antiferromagnet/ferromagnet heterostructures is studied to show the capability of the material system to form artificial neurons and synapses for asynchronous spiking neural networks. The magnetization switching, driven by a single current pulse or trains of pulses, is examined as a function of the pulse width (1 s to 1 ns), amplitude, number, and pulse‐to‐pulse interval. Based on this dynamics and the unique ability of the system to exhibit binary or analog behavior depending on the device size, key functionalities of a synapse (spike‐timing‐dependent plasticity) and a neuron (leaky integrate‐and‐fire) are reproduced in the same material and on the basis of the same working principle. These results open a way toward spintronics‐based neuromorphic hardware that executes cognitive tasks with the efficiency of the human brain.

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Magnetic heterostructures consisting of high-resistivity (238 ± 5 µΩ cm)-W/CoFeB/MgO are prepared by sputtering and their spin-orbit torques are evaluated as a function of W thickness through an extended harmonic measurement. W thickness dependence of the spin-orbit torque with the Slonczewski-like symmetry is well described by the drift-diffusion model with an efficiency parameter, the so-called effective spin Hall angle, of −0.62 ± 0.03. In contrast, the field-like spin-orbit torque is one order of magnitude smaller than the Slonczewski-like torque and shows no appreciable dependence on the W thickness, suggesting a different origin from the Slonczewski-like torque. The results indicate that high-resistivity W is promising for low-current and reliable spin-orbit torque-controlled devices.

BackgroundWRAP53, including α, β and γ isoforms, plays an important role not only in the stability of p53 mRNA, but also in the assembly and trafficking of the telomerase holoenzyme. It has been considered an oncogene and is thought to promote the survival of cancer cells. The aim of this study was to detect the role of TCAB1 (except WRAP53α) in the occurrence and development of head and neck carcinomas.MethodsImmunohistochemistry was used to detect the TCAB1 expression in clinical specimen sections and performed western blotting to check the TCAB1 expression levels in cell lines. TCAB1 was depleted using shRNA lentivirus and the knockdown efficiency was assessed using q-PCR and Western blotting. We performed CCK-8 assays and flow cytometry to check the cell proliferation potential and used the trans-well assay to test the invasion ability in vitro. Xenografts were used to detect the tumor formation potential in vivo. Moreover, we performed cDNA microarray to investigate the candidate factors involved in this process.ResultsWe observed a notable overexpression of TCAB1 in head and neck carcinoma clinical specimens as well as in carcinoma cell lines. Knockdown of TCAB1 decreased the cellular proliferation potential and invasion ability in vitro. cDNA microarray analysis suggested the possible involvement of several pathways and factors associated with tumorigenesis and carcinoma development in the TCAB1-mediated regulation of cancers. Furthermore, the xenograft assay confirmed that the depletion of TCAB1 would inhibit tumor formation in nude mice. The immunohistochemistry results of the mice tumor tissue sections revealed that the cells in shTCAB1 xenografts showed decreased proliferation potential and increased apoptotic trend, meanwhile, the angiogenesis was inhibited in the smaller tumors form shTCAB1 cells.ConclusionsOur study demonstrated that depletion of TCAB1 decreased cellular proliferation and invasion potential both in vitro and in vivo. The data indicated that TCAB1 might facilitate the occurrence and development of head and neck carcinomas. In future, TCAB1 might be useful as a prognostic biomarker or a potential target for the diagnosis and therapy of head and neck carcinomas.

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