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Hideo Ohno - One of the best experts on this subject based on the ideXlab platform.
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electric field effect on spin wave resonance in a nanoscale cofeb mgo Magnetic Tunnel Junction
Applied Physics Letters, 2017Co-Authors: Takaaki Dohi, Shun Kanai, F Matsukura, Hideo OhnoAbstract:We investigate the electric-field effect on the exchange stiffness constant in a CoFeB/MgO Junction through the observation of the spin-wave resonance in a nanoscale Magnetic Tunnel Junction. We evaluate the electric-field dependence of the stiffness constant from the separation between resonance fields for the Kittel and spin-wave modes under electric fields. The obtained stiffness constant increases when the interfacial electron density is decreased. This dependence is consistent with that determined from the observation of electric-field dependent domain structures.
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in plane anisotropy of a nano scaled Magnetic Tunnel Junction with perpendicular Magnetic easy axis
Japanese Journal of Applied Physics, 2015Co-Authors: Eriko Hirayama, Shoji Ikeda, Shun Kanai, H Sato, F Matsukura, Koji Sato, Michihiko Yamanouchi, Hideo OhnoAbstract:We investigate Magnetic properties of a 100-nm-diameter CoFeB/MgO Magnetic Tunnel Junction (MTJ) with perpendicular Magnetic easy axis by homodyne-detected ferroMagnetic resonance (FMR) and Junction resistance measurements. The resonant frequency depends clearly on the direction of the in-plane Magnetic field, which is also the case for the angle dependence of the Junction resistance. A good correspondence between the two independent measurements indicates the presence of unintentionally introduced in-plane Magnetic anisotropy in the present MTJ.
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magnetization switching in a cofeb mgo Magnetic Tunnel Junction by combining spin transfer torque and electric field effect
Applied Physics Letters, 2014Co-Authors: Shun Kanai, H Sato, M Yamanouchi, F Matsukura, Yoshinobu Nakatani, Hideo OhnoAbstract:We propose and demonstrate a scheme for magnetization switching in Magnetic Tunnel Junctions, in which two successive voltage pulses are applied to utilize both spin-transfer torque and electric field effect. Under this switching scheme, a CoFeB/MgO Magnetic Tunnel Junction with perpendicular Magnetic easy axis is shown to switch faster than by spin-transfer torque alone and more reliably than that by electric fields alone.
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wide operational margin capability of 1 kbit spin transfer torque memory array chip with 1 pmos and 1 bottom pin Magnetic Tunnel Junction type cell
Japanese Journal of Applied Physics, 2014Co-Authors: H Koike, Shoji Ikeda, Takashi Ohsawa, Hideo Ohno, Takahiro Hanyu, Hiroaki Honjo, Sadahiko Miura, Tetsuo EndohAbstract:This paper discusses the optimal combination of 1 transistor (T) and 1 Magnetic Tunnel Junction (MTJ) type cell for spin transfer torque memory. Taking into consideration of current magnitude for both the T and the MTJ, either PMOS — bottom pin structure or NMOS — top pin structure can be a promising choice. Focusing on the PMOS–bottom pin structure from the viewpoint of avoiding process difficulty, we clarified the condition that the structure would be effective. In order to verify the structure's effectiveness, a stand-alone MTJ test element group and a 1 kbit memory array chip were designed and fabricated with 90 nm CMOS/100 nm MTJ process. With the pass bit percentage measurement of the memory chip, we successfully demonstrated that 1-PMOS and 1-bottom-pin-MTJ has the wide operation margin of 100% pass at near 1.6 V. It will be an effective solution for 1T–1MTJ memories.
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comprehensive study of cofeb mgo Magnetic Tunnel Junction characteristics with single and double interface scaling down to 1x nm
International Electron Devices Meeting, 2013Co-Authors: H Sato, Naoki Kasai, T Yamamoto, M Yamanouchi, Shunsuke Fukami, Keizo Kinoshita, F Matsukura, Hideo OhnoAbstract:We study characteristics of CoFeB-MgO Magnetic Tunnel Junction with perpendicular easy-axis (p-MTJ) at a reduced dimension down to 1X nm fabricated by hard-mask process. CoFeB-MgO p-MTJ with double-interface shows higher thermal stability down to 1X nm than that with single-interface. Thermal stability factor of 58 and intrinsic critical current of 24 μA are obtained in the CoFeB-MgO Magnetic Tunnel Junction with perpendicular easy-axis using double-interface structure at a diameter of 20 nmφ.
Shun Kanai - One of the best experts on this subject based on the ideXlab platform.
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electric field effect on spin wave resonance in a nanoscale cofeb mgo Magnetic Tunnel Junction
Applied Physics Letters, 2017Co-Authors: Takaaki Dohi, Shun Kanai, F Matsukura, Hideo OhnoAbstract:We investigate the electric-field effect on the exchange stiffness constant in a CoFeB/MgO Junction through the observation of the spin-wave resonance in a nanoscale Magnetic Tunnel Junction. We evaluate the electric-field dependence of the stiffness constant from the separation between resonance fields for the Kittel and spin-wave modes under electric fields. The obtained stiffness constant increases when the interfacial electron density is decreased. This dependence is consistent with that determined from the observation of electric-field dependent domain structures.
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in plane anisotropy of a nano scaled Magnetic Tunnel Junction with perpendicular Magnetic easy axis
Japanese Journal of Applied Physics, 2015Co-Authors: Eriko Hirayama, Shoji Ikeda, Shun Kanai, H Sato, F Matsukura, Koji Sato, Michihiko Yamanouchi, Hideo OhnoAbstract:We investigate Magnetic properties of a 100-nm-diameter CoFeB/MgO Magnetic Tunnel Junction (MTJ) with perpendicular Magnetic easy axis by homodyne-detected ferroMagnetic resonance (FMR) and Junction resistance measurements. The resonant frequency depends clearly on the direction of the in-plane Magnetic field, which is also the case for the angle dependence of the Junction resistance. A good correspondence between the two independent measurements indicates the presence of unintentionally introduced in-plane Magnetic anisotropy in the present MTJ.
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electric field induced ferroMagnetic resonance in a cofeb mgo Magnetic Tunnel Junction under dc bias voltages
Applied Physics Letters, 2014Co-Authors: Shun Kanai, F Matsukura, Daniel C Worledge, Martin Gajek, H OhnoAbstract:We measure homodyne-detected ferroMagnetic resonance (FMR) induced by the electric-field effect in a CoFeB/MgO/CoFeB Magnetic Tunnel Junction (MTJ) with perpendicular Magnetic easy axis under dc bias voltages up to 0.1 V. From the bias dependence of the resonant frequency, we find that the first order perpendicular Magnetic anisotropy is modulated by the applied electric field, whereas the second order component is virtually independent of the electric field. The lineshapes of the FMR spectra are bias dependent, which are explained by the combination of electric-field effect and reflection of the bias voltage from the MTJ.
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magnetization switching in a cofeb mgo Magnetic Tunnel Junction by combining spin transfer torque and electric field effect
Applied Physics Letters, 2014Co-Authors: Shun Kanai, H Sato, M Yamanouchi, F Matsukura, Yoshinobu Nakatani, Hideo OhnoAbstract:We propose and demonstrate a scheme for magnetization switching in Magnetic Tunnel Junctions, in which two successive voltage pulses are applied to utilize both spin-transfer torque and electric field effect. Under this switching scheme, a CoFeB/MgO Magnetic Tunnel Junction with perpendicular Magnetic easy axis is shown to switch faster than by spin-transfer torque alone and more reliably than that by electric fields alone.
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observation of boron diffusion in an annealed ta cofeb mgo Magnetic Tunnel Junction with standing wave hard x ray photoemission
Applied Physics Letters, 2012Co-Authors: A A Greer, Shun Kanai, A X Gray, Shigenori Ueda, Yoshiyuki Yamashita, A M Kaiser, C Bordel, Gunnar K Palsson, N Maejima, Seehun YangAbstract:The CoFeB/MgO system shows promise as a Magnetic Tunnel Junction with perpendicular magnetization and low critical current densities for spin-torque driven magnetization switching. The distribution of B after annealing is believed to be critical to performance. We have studied the distribution of B in a Ta/Co0.2Fe0.6B0.2/MgO sample annealed at 300 °C for 1 h with standing-wave hard x-ray photoemission spectroscopy (SW-HXPS). Comparing experimental rocking curve data to x-ray optical calculations indicates diffusion of 19.5% of the B uniformly into the MgO and of 23.5% into a thin TaB interface layer. SW-HXPS is effective for probing depth distributions in such spintronic structures.
F Matsukura - One of the best experts on this subject based on the ideXlab platform.
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electric field effect on spin wave resonance in a nanoscale cofeb mgo Magnetic Tunnel Junction
Applied Physics Letters, 2017Co-Authors: Takaaki Dohi, Shun Kanai, F Matsukura, Hideo OhnoAbstract:We investigate the electric-field effect on the exchange stiffness constant in a CoFeB/MgO Junction through the observation of the spin-wave resonance in a nanoscale Magnetic Tunnel Junction. We evaluate the electric-field dependence of the stiffness constant from the separation between resonance fields for the Kittel and spin-wave modes under electric fields. The obtained stiffness constant increases when the interfacial electron density is decreased. This dependence is consistent with that determined from the observation of electric-field dependent domain structures.
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free and reference layer magnetization modes versus in plane Magnetic field in a Magnetic Tunnel Junction with perpendicular Magnetic easy axis
Physical Review B, 2016Co-Authors: Hamid Mazraati, Shoji Ikeda, H Ohno, F Matsukura, Eriko Hirayama, Ahmad A Awad, Sunjae Chung, Johan AkermanAbstract:We study the magnetodynamic modes of a Magnetic Tunnel Junction with perpendicular Magnetic easy axis (p-MTJ) in in-plane Magnetic fields using device-level ferroMagnetic resonance spectroscopy. We ...
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in plane anisotropy of a nano scaled Magnetic Tunnel Junction with perpendicular Magnetic easy axis
Japanese Journal of Applied Physics, 2015Co-Authors: Eriko Hirayama, Shoji Ikeda, Shun Kanai, H Sato, F Matsukura, Koji Sato, Michihiko Yamanouchi, Hideo OhnoAbstract:We investigate Magnetic properties of a 100-nm-diameter CoFeB/MgO Magnetic Tunnel Junction (MTJ) with perpendicular Magnetic easy axis by homodyne-detected ferroMagnetic resonance (FMR) and Junction resistance measurements. The resonant frequency depends clearly on the direction of the in-plane Magnetic field, which is also the case for the angle dependence of the Junction resistance. A good correspondence between the two independent measurements indicates the presence of unintentionally introduced in-plane Magnetic anisotropy in the present MTJ.
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electric field induced ferroMagnetic resonance in a cofeb mgo Magnetic Tunnel Junction under dc bias voltages
Applied Physics Letters, 2014Co-Authors: Shun Kanai, F Matsukura, Daniel C Worledge, Martin Gajek, H OhnoAbstract:We measure homodyne-detected ferroMagnetic resonance (FMR) induced by the electric-field effect in a CoFeB/MgO/CoFeB Magnetic Tunnel Junction (MTJ) with perpendicular Magnetic easy axis under dc bias voltages up to 0.1 V. From the bias dependence of the resonant frequency, we find that the first order perpendicular Magnetic anisotropy is modulated by the applied electric field, whereas the second order component is virtually independent of the electric field. The lineshapes of the FMR spectra are bias dependent, which are explained by the combination of electric-field effect and reflection of the bias voltage from the MTJ.
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magnetization switching in a cofeb mgo Magnetic Tunnel Junction by combining spin transfer torque and electric field effect
Applied Physics Letters, 2014Co-Authors: Shun Kanai, H Sato, M Yamanouchi, F Matsukura, Yoshinobu Nakatani, Hideo OhnoAbstract:We propose and demonstrate a scheme for magnetization switching in Magnetic Tunnel Junctions, in which two successive voltage pulses are applied to utilize both spin-transfer torque and electric field effect. Under this switching scheme, a CoFeB/MgO Magnetic Tunnel Junction with perpendicular Magnetic easy axis is shown to switch faster than by spin-transfer torque alone and more reliably than that by electric fields alone.
H Sato - One of the best experts on this subject based on the ideXlab platform.
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10 nmf perpendicular anisotropy cofeb mgo Magnetic Tunnel Junction with over 400 c high thermal tolerance by boron diffusion control
Symposium on VLSI Technology, 2015Co-Authors: H Honjo, H Sato, S Ikeda, Soshi Sato, T Watanebe, S Miura, T Nasuno, Y Noguchi, M Yasuhira, T TanigawaAbstract:We have developed a perpendicular-anisotropy Magnetic Tunnel Junction (p-MTJ) stack with CoFeB free layer and Co/Pt multilayer based synthetic ferriMagnetic (SyF) pinned layer that withstand annealing at a temperature up to 420°C (that compatible with CMOS BEOL process) by controlling boron diffusion. We demonstrated the 10 nmφ p-MTJ with double CoFeB/MgO interface tolerable against 400°C annealing which is a requisite building block for realization of high density spin transfer torque Magnetic random access memory (STT-MRAM) in reduced dimensions.
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in plane anisotropy of a nano scaled Magnetic Tunnel Junction with perpendicular Magnetic easy axis
Japanese Journal of Applied Physics, 2015Co-Authors: Eriko Hirayama, Shoji Ikeda, Shun Kanai, H Sato, F Matsukura, Koji Sato, Michihiko Yamanouchi, Hideo OhnoAbstract:We investigate Magnetic properties of a 100-nm-diameter CoFeB/MgO Magnetic Tunnel Junction (MTJ) with perpendicular Magnetic easy axis by homodyne-detected ferroMagnetic resonance (FMR) and Junction resistance measurements. The resonant frequency depends clearly on the direction of the in-plane Magnetic field, which is also the case for the angle dependence of the Junction resistance. A good correspondence between the two independent measurements indicates the presence of unintentionally introduced in-plane Magnetic anisotropy in the present MTJ.
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magnetization switching in a cofeb mgo Magnetic Tunnel Junction by combining spin transfer torque and electric field effect
Applied Physics Letters, 2014Co-Authors: Shun Kanai, H Sato, M Yamanouchi, F Matsukura, Yoshinobu Nakatani, Hideo OhnoAbstract:We propose and demonstrate a scheme for magnetization switching in Magnetic Tunnel Junctions, in which two successive voltage pulses are applied to utilize both spin-transfer torque and electric field effect. Under this switching scheme, a CoFeB/MgO Magnetic Tunnel Junction with perpendicular Magnetic easy axis is shown to switch faster than by spin-transfer torque alone and more reliably than that by electric fields alone.
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design and fabrication of a perpendicular Magnetic Tunnel Junction based nonvolatile programmable switch achieving 40 less area using shared control transistor structure
Journal of Applied Physics, 2014Co-Authors: Daisuke Suzuki, H Sato, Shunsuke Fukami, Keizo Kinoshita, Masanori Natsui, S Ikeda, S Miura, Akira Mochizuki, Hiroaki Honjo, Tetsuo EndohAbstract:A compact nonvolatile programmable switch (NVPS) using 90 nm CMOS technology together with perpendicular Magnetic Tunnel Junction (p-MTJ) devices is fabricated for zero-standby-power field-programmable gate array. Because routing information does not change once it is programmed into an NVPS, high-speed read and write accesses are not required and a write-control transistor can be shared among all the NVPSs, which greatly simplifies structure of the NVPS. In fact, the effective area of the proposed NVPS is reduced by 40% compared to that of a conventional MTJ-based NVPS. The instant on/off behavior without external nonvolatile memory access is also demonstrated using the fabricated test chip.
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comprehensive study of cofeb mgo Magnetic Tunnel Junction characteristics with single and double interface scaling down to 1x nm
International Electron Devices Meeting, 2013Co-Authors: H Sato, Naoki Kasai, T Yamamoto, M Yamanouchi, Shunsuke Fukami, Keizo Kinoshita, F Matsukura, Hideo OhnoAbstract:We study characteristics of CoFeB-MgO Magnetic Tunnel Junction with perpendicular easy-axis (p-MTJ) at a reduced dimension down to 1X nm fabricated by hard-mask process. CoFeB-MgO p-MTJ with double-interface shows higher thermal stability down to 1X nm than that with single-interface. Thermal stability factor of 58 and intrinsic critical current of 24 μA are obtained in the CoFeB-MgO Magnetic Tunnel Junction with perpendicular easy-axis using double-interface structure at a diameter of 20 nmφ.
M Yamanouchi - One of the best experts on this subject based on the ideXlab platform.
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magnetization switching in a cofeb mgo Magnetic Tunnel Junction by combining spin transfer torque and electric field effect
Applied Physics Letters, 2014Co-Authors: Shun Kanai, H Sato, M Yamanouchi, F Matsukura, Yoshinobu Nakatani, Hideo OhnoAbstract:We propose and demonstrate a scheme for magnetization switching in Magnetic Tunnel Junctions, in which two successive voltage pulses are applied to utilize both spin-transfer torque and electric field effect. Under this switching scheme, a CoFeB/MgO Magnetic Tunnel Junction with perpendicular Magnetic easy axis is shown to switch faster than by spin-transfer torque alone and more reliably than that by electric fields alone.
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comprehensive study of cofeb mgo Magnetic Tunnel Junction characteristics with single and double interface scaling down to 1x nm
International Electron Devices Meeting, 2013Co-Authors: H Sato, Naoki Kasai, T Yamamoto, M Yamanouchi, Shunsuke Fukami, Keizo Kinoshita, F Matsukura, Hideo OhnoAbstract:We study characteristics of CoFeB-MgO Magnetic Tunnel Junction with perpendicular easy-axis (p-MTJ) at a reduced dimension down to 1X nm fabricated by hard-mask process. CoFeB-MgO p-MTJ with double-interface shows higher thermal stability down to 1X nm than that with single-interface. Thermal stability factor of 58 and intrinsic critical current of 24 μA are obtained in the CoFeB-MgO Magnetic Tunnel Junction with perpendicular easy-axis using double-interface structure at a diameter of 20 nmφ.
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three terminal Magnetic Tunnel Junction utilizing the spin hall effect of iridium doped copper
Applied Physics Letters, 2013Co-Authors: M Yamanouchi, H Sato, Shunsuke Fukami, F Matsukura, Lin Chen, J Kim, Masamitsu Hayashi, Hideo OhnoAbstract:We show a three terminal Magnetic Tunnel Junction (MTJ) with a 10-nm thick channel based on an interconnection material Cu with 10% Ir doping. By applying a current density of less than 1012 A m−2 to the channel, depending on the current direction, switching of a MTJ defined on the channel takes place. We show that spin transfer torque (STT) plays a critical role in determining the threshold current. By assuming the spin Hall effect in the channel being the source of the STT, the lower bound of magnitude of the spin Hall angle is evaluated to be 0.03.
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electric field induced magnetization reversal in a perpendicular anisotropy cofeb mgo Magnetic Tunnel Junction
Applied Physics Letters, 2012Co-Authors: Shun Kanai, Shoji Ikeda, M Yamanouchi, Yoshinobu Nakatani, Hideo OhnoAbstract:The electric field-induced ∼180° magnetization reversal is realized for a sputtered CoFeB/MgO-based Magnetic Tunnel Junction with perpendicular Magnetic easy axis in a static external Magnetic field. Application of bias voltage with nanoseconds duration results in a temporal change of Magnetic easy axis in the free layer CoFeB to in-plane, which induces precessional motion of magnetization in the free layer. The magnetization reversal takes place when the bias voltage pulse duration is adjusted to a half period of the precession. We show that the back and forth magnetization reversal can be observed by using successive application of half-period voltage pulses.