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Daichi Chiba - One of the best experts on this subject based on the ideXlab platform.
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electric field effect on the Magnetic Domain Wall creep velocity in pt co pd structures with different co thicknesses
Applied Physics Letters, 2020Co-Authors: Tomohiro Koyama, Junichi Ieda, Daichi ChibaAbstract:The electric field (EF) modulation of Magnetic Domain Wall (DW) creep velocity v in the Pt/Co/Pd structure with perpendicular Magnetic anisotropy (MA) has been studied. The structures with different Co thicknesses tCo up to ∼1 nm are investigated. In all samples, applying a gate voltage induces a clear change in v. Thicker samples provide a higher v modulation efficiency, and the v modulation magnitude of more than a factor of 100 times is observed in the thickest tCo of 0.98 nm. The parameter characterizing the creep motion is significantly affected by the EF, resulting in the modulation of v. Unlike the v case, the MA modulation efficiency decreases with increasing tCo. The present results are discussed based on the EF-induced change in the interfacial Dzyaloshinskii–Moriya interaction (iDMI), which has been recently demonstrated in the same structure, and tCo dependence of the DW energy. The tCo dependence of the v modulation suggests that the EF effect on the iDMI is more important than the MA.
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determination of effective field induced by spin orbit torque using Magnetic Domain Wall creep in pt co structure
Physical Review B, 2015Co-Authors: Tomohiro Koyama, Daichi ChibaAbstract:We investigated the effect of electric current on the Magnetic-field-driven Magnetic Domain Wall (DW) creep velocity in ultrathin Co with perpendicular Magnetic anisotropy deposited on a Pt underlayer. The DW velocity was considerably modulated by the current, and its field dependence deviated from the scaling law with the critical exponent of 1/4, which is generally valid in ferroMagnetic metals. This characteristic feature of the DW motion can be explained by considering the perpendicular effective field generated by spin-orbit torque at the Pt/Co interface. From the relation between the injected current and the modified creep velocity, the determination of the effective field was demonstrated.
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20 nm Magnetic Domain Wall motion memory with ultralow power operation
International Electron Devices Meeting, 2013Co-Authors: Shunsuke Fukami, Daichi Chiba, Noboru Sakimura, Tetsuhiro Suzuki, M Yamanouchi, Kabjin Kim, S Ikeda, Tadahiko Sugibayashi, Naoki Kasai, Teruo OnoAbstract:We study the write and retention properties of Magnetic Domain Wall (DW)-motion memory devices with the dimensions down to 20 nm. We find that the write current and time are scaled along with device size while sufficient thermal stability and low error rate are maintained. As a result, ultralow-power (a few fJ) and reliable operation is possible even at reduced dimensions.
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two barrier stability that allows low power operation in current induced Domain Wall motion
Nature Communications, 2013Co-Authors: Ryo Hiramatsu, Daichi Chiba, Yoko Yoshimura, Yoshinobu Nakatani, Tomohiro Koyama, Kohei Ueda, Kensuke Kobayashi, Masato YamanouchiAbstract:Controlling Magnetic Domain Wall motion in nanowires requires a thorough knowledge of the depinning mechanisms. Here, the authors show that current-induced intrinsic depinning has a different energy barrier than Magnetic field-induced extrinsic depinning, and succeed in quantifying the respective barriers.
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current induced Magnetic Domain Wall motion below intrinsic threshold triggered by walker breakdown
Nature Nanotechnology, 2012Co-Authors: Tomohiro Koyama, Daichi Chiba, Yoko Yoshimura, Kohei Ueda, Kabjin Kim, J P Jamet, A Mougin, K Yamada, A ThiavilleAbstract:Current-induced Magnetic Domain Wall motion can be triggered by an applied Magnetic field, and its motion is described by the vector sum of the velocities imparted by current and Magnetic field driving terms.
Sebastiaan Van Dijken - One of the best experts on this subject based on the ideXlab platform.
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Reversible electric-field-driven Magnetic Domain-Wall motion
Physical Review X, 2015Co-Authors: Kévin J. A. Franke, Ben Van De Wiele, Yasuhiro Shirahata, Sampo J. Hämäläinen, Tomoyasu Taniyama, Sebastiaan Van DijkenAbstract:Control of Magnetic Domain-Wall motion by electric fields has recently attracted scientific attention because of its potential for Magnetic logic and memory devices. Here, we report on a new driving mechanism that allows for Magnetic Domain-Wall motion in an applied electric field without the concurrent use of a Magnetic field or spin-polarized electric current. The mechanism is based on elastic coupling between Magnetic and ferroelectric Domain Walls in multiferroic heterostructures. Pure electric-field-driven Magnetic Domain-Wall motion is demonstrated for epitaxial Fe films on BaTiO3 with in-plane and out-of-plane polarized Domains. In this system, Magnetic Domain-Wall motion is fully reversible and the velocity of the Walls varies exponentially as a function of out-of-plane electric-field strength.
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reversible electric field driven Magnetic Domain Wall motion
Physical Review X, 2015Co-Authors: Kévin J. A. Franke, Ben Van De Wiele, Yasuhiro Shirahata, Sampo J. Hämäläinen, Tomoyasu Taniyama, Sebastiaan Van DijkenAbstract:Researchers demonstrate a low-power way to reversibly drive Magnetic Domain Walls using electric fields.
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electric field driven Magnetic Domain Wall motion in ferroMagnetic ferroelectric heterostructures
arXiv: Materials Science, 2014Co-Authors: Ben Van De Wiele, Kévin J. A. Franke, Lasse Laurson, Sebastiaan Van DijkenAbstract:We investigate Magnetic Domain Wall (MDW) dynamics induced by applied electric fields in ferroMagnetic-ferroelectric thin-film heterostructures. In contrast to conventional driving mechanisms where MDW motion is induced directly by Magnetic fields or electric currents, MDW motion arises here as a result of strong pinning of MDWs onto ferroelectric Domain Walls (FDWs) via local strain coupling. By performing extensive microMagnetic simulations, we find several dynamical regimes, including instabilities such as spin wave emission and complex transformations of the MDW structure. In all cases, the time-averaged MDW velocity equals that of the FDW, indicating the absence of Walker breakdown.
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electric field control of Magnetic Domain Wall motion and local magnetization reversal
arXiv: Materials Science, 2011Co-Authors: Tuomas H E Lahtinen, Kévin J. A. Franke, Sebastiaan Van DijkenAbstract:Spintronic devices currently rely on Magnetic switching or controlled motion of Domain Walls by an external Magnetic field or spin-polarized current. Achieving the same degree of Magnetic controllability using an electric field has potential advantages including enhanced functionality and low power consumption. Here, we report on an approach to electrically control local Magnetic properties, including the writing and erasure of regular ferroMagnetic Domain patterns and the motion of Magnetic Domain Walls, in multiferroic CoFe-BaTiO3 heterostructures. Our method is based on recurrent strain transfer from ferroelastic Domains in ferroelectric media to continuous magnetostrictive films with negligible magnetocrystalline anisotropy. Optical polarization microscopy of both ferroMagnetic and ferroelectric Domain structures reveals that Domain correlations and strong inter-ferroic Domain Wall pinning persist in an applied electric field. This leads to an unprecedented electric controllability over the ferroMagnetic microstructure, an accomplishment that produces giant magnetoelectric coupling effects and opens the way to multiferroic spintronic devices.
Tomohiro Koyama - One of the best experts on this subject based on the ideXlab platform.
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electric field effect on the Magnetic Domain Wall creep velocity in pt co pd structures with different co thicknesses
Applied Physics Letters, 2020Co-Authors: Tomohiro Koyama, Junichi Ieda, Daichi ChibaAbstract:The electric field (EF) modulation of Magnetic Domain Wall (DW) creep velocity v in the Pt/Co/Pd structure with perpendicular Magnetic anisotropy (MA) has been studied. The structures with different Co thicknesses tCo up to ∼1 nm are investigated. In all samples, applying a gate voltage induces a clear change in v. Thicker samples provide a higher v modulation efficiency, and the v modulation magnitude of more than a factor of 100 times is observed in the thickest tCo of 0.98 nm. The parameter characterizing the creep motion is significantly affected by the EF, resulting in the modulation of v. Unlike the v case, the MA modulation efficiency decreases with increasing tCo. The present results are discussed based on the EF-induced change in the interfacial Dzyaloshinskii–Moriya interaction (iDMI), which has been recently demonstrated in the same structure, and tCo dependence of the DW energy. The tCo dependence of the v modulation suggests that the EF effect on the iDMI is more important than the MA.
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determination of effective field induced by spin orbit torque using Magnetic Domain Wall creep in pt co structure
Physical Review B, 2015Co-Authors: Tomohiro Koyama, Daichi ChibaAbstract:We investigated the effect of electric current on the Magnetic-field-driven Magnetic Domain Wall (DW) creep velocity in ultrathin Co with perpendicular Magnetic anisotropy deposited on a Pt underlayer. The DW velocity was considerably modulated by the current, and its field dependence deviated from the scaling law with the critical exponent of 1/4, which is generally valid in ferroMagnetic metals. This characteristic feature of the DW motion can be explained by considering the perpendicular effective field generated by spin-orbit torque at the Pt/Co interface. From the relation between the injected current and the modified creep velocity, the determination of the effective field was demonstrated.
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two barrier stability that allows low power operation in current induced Domain Wall motion
Nature Communications, 2013Co-Authors: Ryo Hiramatsu, Daichi Chiba, Yoko Yoshimura, Yoshinobu Nakatani, Tomohiro Koyama, Kohei Ueda, Kensuke Kobayashi, Masato YamanouchiAbstract:Controlling Magnetic Domain Wall motion in nanowires requires a thorough knowledge of the depinning mechanisms. Here, the authors show that current-induced intrinsic depinning has a different energy barrier than Magnetic field-induced extrinsic depinning, and succeed in quantifying the respective barriers.
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current induced Magnetic Domain Wall motion below intrinsic threshold triggered by walker breakdown
Nature Nanotechnology, 2012Co-Authors: Tomohiro Koyama, Daichi Chiba, Yoko Yoshimura, Kohei Ueda, Kabjin Kim, J P Jamet, A Mougin, K Yamada, A ThiavilleAbstract:Current-induced Magnetic Domain Wall motion can be triggered by an applied Magnetic field, and its motion is described by the vector sum of the velocities imparted by current and Magnetic field driving terms.
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Magnetic field insensitivity of Magnetic Domain Wall velocity induced by electrical current in co ni nanowire
Applied Physics Letters, 2011Co-Authors: Tomohiro Koyama, Daichi Chiba, Yoshinobu Nakatani, Kohei Ueda, Shunsuke Fukami, H Tanigawa, Toshiyasu Suzuki, N Ohshima, Nobuyuki Ishiwata, Teruo OnoAbstract:We have investigated the velocity of Magnetic Domain Wall (DW) motion induced by electric currents in a Co/Ni nanowire with a perpendicular Magnetic anisotropy. The DW velocity increased as current density increased and the maximum velocity of 60 m/s was observed. Furthermore, the DW velocity was found to be almost independent of external perpendicular Magnetic fields in the range of −50 to +50 Oe. The mechanism of the observed field insensitivity of the current induced DW motion is also discussed.
Kévin J. A. Franke - One of the best experts on this subject based on the ideXlab platform.
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Reversible electric-field-driven Magnetic Domain-Wall motion
Physical Review X, 2015Co-Authors: Kévin J. A. Franke, Ben Van De Wiele, Yasuhiro Shirahata, Sampo J. Hämäläinen, Tomoyasu Taniyama, Sebastiaan Van DijkenAbstract:Control of Magnetic Domain-Wall motion by electric fields has recently attracted scientific attention because of its potential for Magnetic logic and memory devices. Here, we report on a new driving mechanism that allows for Magnetic Domain-Wall motion in an applied electric field without the concurrent use of a Magnetic field or spin-polarized electric current. The mechanism is based on elastic coupling between Magnetic and ferroelectric Domain Walls in multiferroic heterostructures. Pure electric-field-driven Magnetic Domain-Wall motion is demonstrated for epitaxial Fe films on BaTiO3 with in-plane and out-of-plane polarized Domains. In this system, Magnetic Domain-Wall motion is fully reversible and the velocity of the Walls varies exponentially as a function of out-of-plane electric-field strength.
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reversible electric field driven Magnetic Domain Wall motion
Physical Review X, 2015Co-Authors: Kévin J. A. Franke, Ben Van De Wiele, Yasuhiro Shirahata, Sampo J. Hämäläinen, Tomoyasu Taniyama, Sebastiaan Van DijkenAbstract:Researchers demonstrate a low-power way to reversibly drive Magnetic Domain Walls using electric fields.
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electric field driven Magnetic Domain Wall motion in ferroMagnetic ferroelectric heterostructures
arXiv: Materials Science, 2014Co-Authors: Ben Van De Wiele, Kévin J. A. Franke, Lasse Laurson, Sebastiaan Van DijkenAbstract:We investigate Magnetic Domain Wall (MDW) dynamics induced by applied electric fields in ferroMagnetic-ferroelectric thin-film heterostructures. In contrast to conventional driving mechanisms where MDW motion is induced directly by Magnetic fields or electric currents, MDW motion arises here as a result of strong pinning of MDWs onto ferroelectric Domain Walls (FDWs) via local strain coupling. By performing extensive microMagnetic simulations, we find several dynamical regimes, including instabilities such as spin wave emission and complex transformations of the MDW structure. In all cases, the time-averaged MDW velocity equals that of the FDW, indicating the absence of Walker breakdown.
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electric field control of Magnetic Domain Wall motion and local magnetization reversal
arXiv: Materials Science, 2011Co-Authors: Tuomas H E Lahtinen, Kévin J. A. Franke, Sebastiaan Van DijkenAbstract:Spintronic devices currently rely on Magnetic switching or controlled motion of Domain Walls by an external Magnetic field or spin-polarized current. Achieving the same degree of Magnetic controllability using an electric field has potential advantages including enhanced functionality and low power consumption. Here, we report on an approach to electrically control local Magnetic properties, including the writing and erasure of regular ferroMagnetic Domain patterns and the motion of Magnetic Domain Walls, in multiferroic CoFe-BaTiO3 heterostructures. Our method is based on recurrent strain transfer from ferroelastic Domains in ferroelectric media to continuous magnetostrictive films with negligible magnetocrystalline anisotropy. Optical polarization microscopy of both ferroMagnetic and ferroelectric Domain structures reveals that Domain correlations and strong inter-ferroic Domain Wall pinning persist in an applied electric field. This leads to an unprecedented electric controllability over the ferroMagnetic microstructure, an accomplishment that produces giant magnetoelectric coupling effects and opens the way to multiferroic spintronic devices.
Bert B Koopmans - One of the best experts on this subject based on the ideXlab platform.
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voltage gated pinning in a Magnetic Domain Wall conduit
Applied Physics Letters, 2013Co-Authors: J Jeroen H Franken, H. J. M. Swagten, Yuxiang Yin, A J Schellekens, A Van Den Brink, Bert B KoopmansAbstract:In spintronic devices relying on Magnetic Domain-Wall (DW) motion, robust control over the DW position is required. We use electric-field control of perpendicular Magnetic anisotropy to create a voltage-gated pinning site in a microstructured Pt/Co/AlOx DW conduit. A DW pins at the edge of a gate electrode, and the strength of pinning can be tuned linearly and reversibly with an efficiency of 0.22(1) mT/V. This result is supported by a microMagnetic model, taking full account of the anisotropy step at the gate edge, which is directly caused by a change in the electron density due to the choice of material.
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shift registers based on Magnetic Domain Wall ratchets with perpendicular anisotropy
Nature Nanotechnology, 2012Co-Authors: J Jeroen H Franken, H. J. M. Swagten, Bert B KoopmansAbstract:Time-varying Magnetic fields can be used to drive Magnetic Domain Walls around arbitrary paths, including closed loops, in a ratchet-like fashion.
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shift registers based on Magnetic Domain Wall ratchets with perpendicular anisotropy
Nature Nanotechnology, 2012Co-Authors: J Jeroen H Franken, H. J. M. Swagten, Bert B KoopmansAbstract:The movement of Magnetic Domain Walls can be used to build a device known as a shift register, which has applications in memory and logic circuits. However, the application of Magnetic Domain Wall shift registers has been hindered by geometrical restrictions, by randomness in Domain Wall displacement and by the need for high current densities or rotating Magnetic fields. Here, we propose a new approach in which the energy landscape experienced by the Domain Walls is engineered to favour a unidirectional ratchet-like propagation. The Domain Walls are defined between Domains with an out-of-plane (perpendicular) magnetization, which allows us to route Domain Walls along arbitrary in-plane paths using a time-varying applied Magnetic field with fixed orientation. In addition, this ratchet-like motion causes the Domain Walls to lock to discrete positions along these paths, which is useful for digital devices. As a proof-of-principle experiment we demonstrate the continuous propagation of two Domain Walls along a closed-loop path in a platinum/cobalt/platinum strip.
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asymmetric pt co pt stack induced sign control of current induced Magnetic Domain Wall creep
Applied Physics Letters, 2012Co-Authors: Reinoud Lavrijsen, H. J. M. Swagten, J Jeroen H Franken, Ppj Haazen, E Mure, J Jurgen T Kohlhepp, Bert B KoopmansAbstract:We report experimentally obtained Magnetic Domain Wall (DW) velocities of current-assisted field-driven DW creep in perpendicularly magnetized Pt/Co/Pt. We have intentionally introduced an asymmetry in the stacks by using different thicknesses of the two Pt layers sandwiching the Co layer. Thereby, it is tested whether conflicting current-induced Domain Wall motion (CI-DWM) results may be intrinsically related to the basic layout and growth. We sketch a scenario which could be at the basis of contradicting reports in literature where the direction of CI-DWM conflicts with spin-torque-transfer theory, allowing the sign of the current-induced effect on DW motion to be tuned.
