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Information dynamics, natural computing and Maxwell's demon in two skyrmions system
Authors:
Yoshishige Suzuki,
Hiroki Mori,
Soma Miki,
Kota Emoto,
Ryo Ishikawa,
Eiiti Tamura,
Hikaru Nomura,
Minori Goto
Abstract:
The probabilistic information flow and natural computational capability of a system with two magnetic skyrmions at room temperature have been experimentally evaluated. Based on this evaluation, an all-solid-state built-in Maxwell's demon operating at room temperature is also proposed. Probabilistic behavior has gained attention for its potential to enable unconventional computing paradigms. Howeve…
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The probabilistic information flow and natural computational capability of a system with two magnetic skyrmions at room temperature have been experimentally evaluated. Based on this evaluation, an all-solid-state built-in Maxwell's demon operating at room temperature is also proposed. Probabilistic behavior has gained attention for its potential to enable unconventional computing paradigms. However, information propagation and computation in such systems are more complex than in conventional computers, making their visualization essential. In this study, a two-skyrmion system confined within a square potential well at thermal equilibrium was analyzed using information thermodynamics. Transfer entropy and the time derivative of mutual information were employed to investigate the information propagation speed, the absence of a Maxwell's demon in thermal equilibrium, and the system's non-Markovian properties. Furthermore, it was demonstrated that the system exhibits a small but finite computational capability for the nonlinear XOR operation, potentially linked to hidden information in the non-Markovian system. Based on these experiments and analyses, an all-solid-state built-in Maxwell's demon utilizing the two-skyrmion system and operating at room temperature is proposed.
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Submitted 15 June, 2025;
originally announced June 2025.
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Simulation study on Conservative Join (C-join) in Skyrmion Brownian circuit
Authors:
H. Imanishi,
E. Tamura,
S. Miki,
R. Ishikawa,
H. Nomura,
M. Goto,
Y. Suzuki
Abstract:
Magnetic skyrmions, which exhibit Brownian motion in solid-state systems, are promising candidates as signal carriers for Brownian computing. However, successfully implementing such systems requires two critical components: a Hub to connect multiple wires and a C-join to synchronize the skyrmion signal carriers. While the former has been successfully addressed, the latter remains a significant cha…
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Magnetic skyrmions, which exhibit Brownian motion in solid-state systems, are promising candidates as signal carriers for Brownian computing. However, successfully implementing such systems requires two critical components: a Hub to connect multiple wires and a C-join to synchronize the skyrmion signal carriers. While the former has been successfully addressed, the latter remains a significant challenge. In this study, we propose a novel solution by decomposing the C-join into two sub-circuits, the Join and Fork, and validate their functionality using a particle simulation approach. Our results demonstrate that the C-join can effectively synchronize skyrmion signals within 6.8μs with a 99.9% success rate at low temperatures. Additionally, we construct the Half-adder in a crossing-free architecture utilizing the C-join circuits. These findings pave the way for the realization of skyrmion-based Brownian computing systems.
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Submitted 11 February, 2025; v1 submitted 8 February, 2025;
originally announced February 2025.
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Transfer Entropy and Flow of Information in Two-Skyrmion System
Authors:
Tenta Tani,
Soma Miki,
Hiroki Mori,
Minori Goto,
Yoshishige Suzuki,
Eiiti Tamura
Abstract:
We theoretically investigate the flow of information in an interacting two-skyrmion system confined in a box at finite temperature. By numerical simulations based on the Thiele-Langevin equation, we demonstrate that the skyrmion motion cannot be fully described by the master equation, highlighting the nontrivial dynamics. Particularly, due to the chiral motion of skyrmion, we find asymmetric flow…
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We theoretically investigate the flow of information in an interacting two-skyrmion system confined in a box at finite temperature. By numerical simulations based on the Thiele-Langevin equation, we demonstrate that the skyrmion motion cannot be fully described by the master equation, highlighting the nontrivial dynamics. Particularly, due to the chiral motion of skyrmion, we find asymmetric flow of information with violating the detailed balance condition. We analyze this system using information-theoretical quantities including Shannon entropy, mutual information, and transfer entropy. The physical significance of transfer entropy, which has been overlooked in previous studies, is elucidated. Notably, the peak position of the transfer entropy, as a function of time delay, is independent of the interaction range yet dependent on the box size. This peak corresponds to the characteristic time required for changing the skyrmion state. Due to the unusual asymmetric circulation of information, the two-skyrmion system can be a unique device for future applications to the natural computing.
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Submitted 9 March, 2026; v1 submitted 24 December, 2024;
originally announced December 2024.
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Control of spin-orbit torques by interface engineering in topological insulator heterostructures
Authors:
Frédéric Bonell,
Minori Goto,
Guillaume Sauthier,
Juan F. Sierra,
Adriana I. Figueroa,
Marius V. Costache,
Shinji Miwa,
Yoshishige Suzuki,
Sergio O. Valenzuela
Abstract:
(Bi$_{1-x}$Sb$_x$)$_2$Te$_3$ topological insulators (TIs) are gathering increasing attention owing to their large charge-to-spin conversion efficiency and the ensuing spin-orbit torques (SOTs) that can be used to manipulate the magnetization of a ferromagnet (FM). The origin of the torques, however, remains elusive, while the implications of hybridized states and the strong material intermixing at…
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(Bi$_{1-x}$Sb$_x$)$_2$Te$_3$ topological insulators (TIs) are gathering increasing attention owing to their large charge-to-spin conversion efficiency and the ensuing spin-orbit torques (SOTs) that can be used to manipulate the magnetization of a ferromagnet (FM). The origin of the torques, however, remains elusive, while the implications of hybridized states and the strong material intermixing at the TI/FM interface are essentially unexplored. By combining interface chemical analysis and spin-transfer ferromagnetic resonance (ST-FMR) measurements, we demonstrate that intermixing plays a critical role in the generation of SOTs. By inserting a suitable normal metal spacer, material intermixing is reduced and the TI properties at the interface are largely improved, resulting in strong variations in the nature of the SOTs. A dramatic enhancement of a field-like torque, opposing and surpassing the Oersted-field torque, is observed, which can be attributed to the non-equilibrium spin density in Rashba-split surface bands and to the suppression of spin memory loss.
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Submitted 17 September, 2020;
originally announced September 2020.
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Over 1% magnetoresistance ratio at room temperature in non-degenerate silicon-based lateral spin valves
Authors:
H. Koike,
S. Lee,
R. Ohshima,
E. Shigematsu,
M. Goto,
S. Miwa,
Y. Suzuki,
T. Sasaki,
Y. Ando,
M. Shiraishi
Abstract:
To augment the magnetoresistance (MR) ratio of n-type non-degenerate Si-based lateral spin valves (Si-LSVs), we modify the doping profile in the Si layer and introduce a larger local strain into the Si channel by changing a capping insulator. The highest MR ratio of 1.4% is achieved in the Si-LSVs through these improvements, with significant roles played by a reduction in the resistance-area produ…
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To augment the magnetoresistance (MR) ratio of n-type non-degenerate Si-based lateral spin valves (Si-LSVs), we modify the doping profile in the Si layer and introduce a larger local strain into the Si channel by changing a capping insulator. The highest MR ratio of 1.4% is achieved in the Si-LSVs through these improvements, with significant roles played by a reduction in the resistance-area product of the ferromagnetic contacts and an enhancement of the momentum relaxation time in the Si channel.
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Submitted 31 August, 2020;
originally announced August 2020.
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Manipulating 1-dimensinal skyrmion motion by external magnetic field gradient
Authors:
Jaehun Cho,
Eiiti Tamura,
Chaozhe Liu,
Soma Miki,
Chun-Yeol You,
June-Seo Kim,
Hikaru Nomura,
Minori Goto,
Ryoichi Nakatani,
Yoshishige Suzuki
Abstract:
We have investigated an analytic formula of the 1-dimensional magnetic skyrmion dynamics under external magnetic field gradient. We find excellent agreement between the analytical model and micromagnetic simulation results for various magnetic parameters such as the magnetic field gradient, Gilbert damping constant. We also observe much faster velocity of the chiral domain wall (DW) motion. The ch…
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We have investigated an analytic formula of the 1-dimensional magnetic skyrmion dynamics under external magnetic field gradient. We find excellent agreement between the analytical model and micromagnetic simulation results for various magnetic parameters such as the magnetic field gradient, Gilbert damping constant. We also observe much faster velocity of the chiral domain wall (DW) motion. The chiral DW is exist with smaller interfacial Dzyaloshinskii-Moriya interaction energy density cases. These results provide to develop efficient control of skyrmion for spintronic devices.
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Submitted 11 May, 2020;
originally announced May 2020.
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Skyrmion confinement and dynamics in tracks patterned with magnetic anisotropy: theory and simulations
Authors:
E. Tamura,
C. Liu,
S. Miki,
J. Cho,
M. Goto,
H. Nomura,
R. Nakatani,
Y. Suzuki
Abstract:
Skyrmion is a topologically protected spin texture excited in magnetic thin films. The radii of skyrmions are typically 10-100 nm. Because of the size, the skyrmion is expected to be a candidate for memory and novel-device usages. To realize the futuristic devices that will be using the skyrmion circuit, the tracks which guide the motion of skyrmions are needed. The tracks patterned with differenc…
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Skyrmion is a topologically protected spin texture excited in magnetic thin films. The radii of skyrmions are typically 10-100 nm. Because of the size, the skyrmion is expected to be a candidate for memory and novel-device usages. To realize the futuristic devices that will be using the skyrmion circuit, the tracks which guide the motion of skyrmions are needed. The tracks patterned with differences in the magnetic-anisotropy energy are well-paved without a potential pocket, whereas the tracks carved out of magnetic films have the potential pockets at corners due to the demagnetizing field. Therefore, the tracks patterned with the magnetic anisotropy plays a key role in making the skyrmion circuits. The experiment along this idea has been conducted for the hub and bent tracks. However, we have little known the motion of skyrmions in these tracks. This work aims to identify the forces acting between skyrmions and walls of the tracks. The static force on a skyrmion can be expressed as minus the gradient of the potential energy caused by the magnetic-anisotropy undulation. The potential can be estimated numerically, modeling the shape of skyrmions with their radii and domain wall widths. We find that the forces depend not only on the distance from the wall but also on the shape of skyrmions. We have also performed micromagnetic simulations where the Magnus force and the acceleration by the magnetic-anisotropy gradient are taken into account as well as the force by the walls. The simulation results show good agreement with those calculated from the modeled skyrmions.
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Submitted 11 May, 2020;
originally announced May 2020.
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Investigation of gating effect in Si spin MOSFET
Authors:
Soobeom Lee,
Fabien Rortais,
Ryo Ohshima,
Yuichiro Ando,
Minori Goto,
Shinji Miwa,
Yoshishige Suzuki,
Hayato Koike,
Masashi Shiraishi
Abstract:
A gate voltage application in a Si-based spin metal-oxide-semiconductor field-effect transistor (spin MOSFET) modulates spin accumulation voltages, where both electrical conductivity and drift velocity are modified while keeping constant electric current. An unprecedented reduction in the spin accumulation voltages in a Si spin MOSFET under negative gate voltage applications is observed in a high…
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A gate voltage application in a Si-based spin metal-oxide-semiconductor field-effect transistor (spin MOSFET) modulates spin accumulation voltages, where both electrical conductivity and drift velocity are modified while keeping constant electric current. An unprecedented reduction in the spin accumulation voltages in a Si spin MOSFET under negative gate voltage applications is observed in a high electric bias current regime. To support our claim, the electric bias current dependence of the spin accumulation voltage under the gate voltage applications is investigated in detail and compared to a spin drift diffusion model including the conductance mismatch effect. We proved that the drastic decrease of the mobility and spin lifetime in the Si channel is due to the optical phonon emission at the high electric bias current, which consequently reduced the spin accumulation voltage.
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Submitted 28 October, 2019;
originally announced October 2019.
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Skyrmion Brownian circuit implemented in a continuous ferromagnetic thin film
Authors:
Yuma Jibiki,
Minori Goto,
Eiiti Tamura,
Jaehun Cho,
Soma Miki,
Hikaru Nomura,
Titiksha Srivastava,
Willy Lim,
Stephane Auffret,
Claire Baraduc,
Helene Bea,
Yoshishige Suzuki
Abstract:
The fabrication of a skyrmion circuit which stabilizes skyrmions is important to realize micro- to nano-sized skyrmion devices. One example of promising skyrmion-based device is Brownian computers, which have been theoretically proposed, but not realized. It would require a skyrmion circuit in which the skyrmion is stabilized and easily movable. However, the usual skyrmion circuits fabricated by e…
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The fabrication of a skyrmion circuit which stabilizes skyrmions is important to realize micro- to nano-sized skyrmion devices. One example of promising skyrmion-based device is Brownian computers, which have been theoretically proposed, but not realized. It would require a skyrmion circuit in which the skyrmion is stabilized and easily movable. However, the usual skyrmion circuits fabricated by etching of the ferromagnetic film decrease the demagnetization field stabilizing the skyrmions, and thus prevent their formation. In this study, a skyrmion Brownian circuit implemented in a continuous ferromagnetic film with patterned SiO$_2$ capping to stabilize the skyrmion formation. The patterned SiO$_2$ capping controls the saturation field of the ferromagnetic layer and forms a wire-shaped skyrmion potential well, which stabilizes skyrmion formation in the circuit. Moreover, we implement a hub (Y-junction) circuit without pinning sites at the junction by patterned SiO$_2$ capping. This technique enables the efficient control of skyrmion-based memory and logic devices, as well as Brownian computers.
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Submitted 10 May, 2020; v1 submitted 22 September, 2019;
originally announced September 2019.
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Gate-tunable spin exclusive or operation in a silicon-based spin device at room temperature
Authors:
R. Ishihara,
Y. Ando,
S. Lee,
M. Goto,
S. Miwa,
Y. Suzuki,
H. Koike,
M. Shiraishi
Abstract:
Room temperature operation of a spin exclusive or (XOR) gate was demonstrated in lateral spin valve devices with nondegenerate silicon (Si) channels. The spin XOR gate is a fundamental part of the magnetic logic gate (MLG) that enables reconfigurable and nonvolatile NAND or OR operation in one device. The device for the spin XOR gate consists of three iron (Fe)/cobalt (Co)/magnesium oxide (MgO) el…
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Room temperature operation of a spin exclusive or (XOR) gate was demonstrated in lateral spin valve devices with nondegenerate silicon (Si) channels. The spin XOR gate is a fundamental part of the magnetic logic gate (MLG) that enables reconfigurable and nonvolatile NAND or OR operation in one device. The device for the spin XOR gate consists of three iron (Fe)/cobalt (Co)/magnesium oxide (MgO) electrodes, i.e., two input and one output electrodes. Spins are injected into the Si channel from the input electrodes whose spin angular momentum corresponds to the binary input 1 or 0. The spin drift effect is controlled by a lateral electric field in the Si channel to adjust the spin accumulation voltages under two different parallel configurations, corresponding to (1, 1) and (0, 0), so that they exhibit the same value. As a result, the spin accumulation voltage detected by the output electrode exhibits three different voltages, represented by an XOR gate. The one-dimensional spin drift-diffusion model clearly explains the obtained XOR behavior. Charge current detection of the spin XOR gate is also demonstrated. The detected charge current has a maximum of 0.94 nA, the highest value in spin XOR gates reported thus far. Furthermore, gate voltage modulation of the spin XOR gate is also demonstrated, which enables operation of multiple MLG devices.
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Submitted 13 September, 2019;
originally announced September 2019.
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Reservoir computing with dipole-coupled nanomagnets
Authors:
Hikaru Nomura,
Taishi Furuta,
Kazuki Tsujimoto,
Yuki Kuwabiraki,
Ferdinand Peper,
Eiiti Tamura,
Shinji Miwa,
Minori Goto,
Ryoichi Nakatani,
Yoshishige Suzuki
Abstract:
The feasibility of reservoir computing based on dipole-coupled nanomagnets is demonstrated using micro-magnetic simulations. The reservoir consists of an 2x10 array of nanomagnets. The static-magnetization directions of the nanomagnets are used as reservoir states. To update these states, we change the magnetization of one nanomagnet according to a single-bit-sequential signal. We also change the…
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The feasibility of reservoir computing based on dipole-coupled nanomagnets is demonstrated using micro-magnetic simulations. The reservoir consists of an 2x10 array of nanomagnets. The static-magnetization directions of the nanomagnets are used as reservoir states. To update these states, we change the magnetization of one nanomagnet according to a single-bit-sequential signal. We also change the uniaxial anisotropy of the other nanomagnets using a voltage-induced magnetic-anisotropy change to enhance information flow, storage, and linear/nonlinear calculations. Binary tasks with AND, OR, and XOR operations were performed to evaluate the performance of the magnetic-array reservoir. The reservoir-computing output matrix was found to be trainable to perform AND, OR, and XOR operations with an input delay of up to three bits.
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Submitted 14 February, 2019; v1 submitted 31 October, 2018;
originally announced October 2018.
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Electric-field-induced changes of magnetic moments and magnetocrystalline anisotropy in ultrathin cobalt films
Authors:
Takeshi Kawabe,
Kohei Yoshikawa,
Masahito Tsujikawa,
Takuya Tsukahara,
Kohei Nawaoka,
Yoshinori Kotani,
Kentaro Toyoki,
Minori Goto,
Motohiro Suzuki,
Tetsuya Nakamura,
Masafumi Shirai,
Yoshishige Suzuki,
Shinji Miwa
Abstract:
In this study, the microscopic origins of the voltage-controlled magnetic anisotropy (VCMA) in 3d-ferromagnetic metals are revealed. Using in-situ X-ray fluorescence spectroscopy that provides a high quantum efficiency, electric-field-induced changes in orbital magnetic moment and magnetic dipole Tz terms in ultrathin Co films are demonstrated. An orbital magnetic moment difference of 0.013μB. was…
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In this study, the microscopic origins of the voltage-controlled magnetic anisotropy (VCMA) in 3d-ferromagnetic metals are revealed. Using in-situ X-ray fluorescence spectroscopy that provides a high quantum efficiency, electric-field-induced changes in orbital magnetic moment and magnetic dipole Tz terms in ultrathin Co films are demonstrated. An orbital magnetic moment difference of 0.013μB. was generated in the presence of electric fields of +(-)0.2 V/nm. The VCMA of Co was properly estimated by the induced change in orbital magnetic moment, according to the perturbation theory model. The induced change in magnetic dipole Tz term only slightly contributed to the VCMA in 3d-ferromagnetic metals.
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Submitted 8 December, 2017; v1 submitted 28 August, 2017;
originally announced August 2017.
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Electric spectroscopy of vortex states and dynamics in magnetic disks
Authors:
Minori Goto,
Hiroshi Hata,
Akinobu Yamaguchi,
Yoshinobu Nakatani,
Takehiro Yamaoka,
Yukio Nozaki,
Hideki Miyajima
Abstract:
Spin-polarized radio frequency (RF) currents and RF-Oersted fields resonantly excite a magnetic vortex core confined in a micron-scale soft magnetic disk. In this study, we measured the rectifying voltage spectra caused by the anisotropic magnetoresistance oscillation due to the gyration of the vortex with different polarity and chirality. The measured spectra are presented such that we can determ…
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Spin-polarized radio frequency (RF) currents and RF-Oersted fields resonantly excite a magnetic vortex core confined in a micron-scale soft magnetic disk. In this study, we measured the rectifying voltage spectra caused by the anisotropic magnetoresistance oscillation due to the gyration of the vortex with different polarity and chirality. The measured spectra are presented such that we can determine the vortex properties and strength of the spin torques and Oersted field accurately and directly through analytical calculation.
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Submitted 22 June, 2011; v1 submitted 22 June, 2011;
originally announced June 2011.
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Characteristic electronic structure and its doping evolution in lightly-doped to underdoped YBa2Cu3Oy
Authors:
H. Yagi,
T. Yoshida,
A. Fujimori,
K. Tanaka,
N. Mannella,
W. L. Yang,
X. J. Zhou,
D. H. Lu,
Z. -X. Shen,
Z. Hussain,
M. Kubota,
K. Ono,
K. Segawa,
Y. Ando,
D. Iijima,
M. Goto,
K. M. Kojima,
S. Uchida
Abstract:
We have performed an angle resolved photoemission spectroscopy (ARPES) study of lightly-doped to underdoped YBa2Cu3Oy (YBCO) untwinned single crystals and a core-level x-ray photoemission spectroscopy (XPS) study of YBCO single and polycrystals. In the zone diagonal (nodal) direction, dispersive quasi-particle (QP) features crossing the Fermi level were observed down to the hole concentration of…
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We have performed an angle resolved photoemission spectroscopy (ARPES) study of lightly-doped to underdoped YBa2Cu3Oy (YBCO) untwinned single crystals and a core-level x-ray photoemission spectroscopy (XPS) study of YBCO single and polycrystals. In the zone diagonal (nodal) direction, dispersive quasi-particle (QP) features crossing the Fermi level were observed down to the hole concentration of ~ 4%, which explains the metallic transport of the lightly-doped YBCO. The chemical potential shift estimated from XPS was more rapid than in the Bi2212 cuprates. Upon hole doping, very rapid spectral weight transfer from high binding energies to the QP feature, even faster than La2-xSrxCuO4, was observed.
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Submitted 3 February, 2010;
originally announced February 2010.
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Muon Spin Relaxation Studies of Magnetic-Field-Induced Effects in High-$T_{c}$ Superconductors
Authors:
A. T. Savici,
A. Fukaya,
I. M. Gat-Malureanu,
T. Ito,
P. L. Russo,
Y. J. Uemura,
C. R. Wiebe,
P. P. Kyriakou,
G. J. MacDougall,
M. T. Rovers,
G. M. Luke,
K. M. Kojima,
M. Goto,
S. Uchida,
R. Kadono,
K. Yamada,
S. Tajima,
T. Masui,
H. Eisaki,
N. Kaneko,
M. Greven,
G. D. Gu
Abstract:
Muon spin relaxation ($μ$SR) measurements in high transverse magnetic fields ($\parallel \hat c$) revealed strong field-induced quasi-static magnetism in the underdoped and Eu doped (La,Sr)$_{2}$CuO$_{4}$ and La$_{1.875}$Ba$_{0.125}$CuO$_{4}$, existing well above $T_{c}$ and $T_{N}$. The susceptibility-counterpart of Cu spin polarization, derived from the muon spin relaxation rate, exhibits a di…
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Muon spin relaxation ($μ$SR) measurements in high transverse magnetic fields ($\parallel \hat c$) revealed strong field-induced quasi-static magnetism in the underdoped and Eu doped (La,Sr)$_{2}$CuO$_{4}$ and La$_{1.875}$Ba$_{0.125}$CuO$_{4}$, existing well above $T_{c}$ and $T_{N}$. The susceptibility-counterpart of Cu spin polarization, derived from the muon spin relaxation rate, exhibits a divergent behavior towards $T \sim 25$ K. No field-induced magnetism was detected in overdoped La$_{1.81}$Sr$_{0.19}$CuO$_{4}$, optimally doped Bi2212, and Zn-doped YBa$_{2}$Cu$_{3}$O$_{7}$.
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Submitted 6 October, 2005; v1 submitted 25 October, 2004;
originally announced October 2004.
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Angle-resolved photoemission study of insulating and metallic Cu-O chains in PrBa$_2$Cu$_3$O$_7$ and PrBa$_2$Cu$_4$O$_8$
Authors:
T. Mizokawa,
C. Kim,
Z. -X. Shen,
A. Ino,
T. Yoshida,
A. Fujimori,
M. Goto,
H. Eisaki,
S. Uchida,
M. Tagami,
K. Yoshida,
A. I. Rykov,
Y. Siohara,
K. Tomimoto,
S. Tajima,
Yuh Yamada,
S. Horii,
N. Yamada,
Yasuji Yamada,
I. Hirabayashi
Abstract:
We compare the angle-resolved photoemission spectra of the hole-doped Cu-O chains in PrBa$_2$Cu$_3$O$_7$ (Pr123) and in PrBa$_2$Cu$_4$O$_8$ (Pr124). While, in Pr123, a dispersive feature from the chain takes a band maximum at $k_b$ (momentum along the chain) $\sim$ $π/4$ and loses its spectral weight around the Fermi level, it reaches the Fermi level at $k_b$ $\sim$ $π/4$ in Pr124. Although the…
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We compare the angle-resolved photoemission spectra of the hole-doped Cu-O chains in PrBa$_2$Cu$_3$O$_7$ (Pr123) and in PrBa$_2$Cu$_4$O$_8$ (Pr124). While, in Pr123, a dispersive feature from the chain takes a band maximum at $k_b$ (momentum along the chain) $\sim$ $π/4$ and loses its spectral weight around the Fermi level, it reaches the Fermi level at $k_b$ $\sim$ $π/4$ in Pr124. Although the chains in Pr123 and Pr124 are approximately 1/4-filled, they show contrasting behaviors: While the chains in Pr123 have an instability to charge ordering, those in Pr124 avoid it and show an interesting spectral feature of a metallic coupled-chain system.
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Submitted 7 November, 2000; v1 submitted 3 November, 2000;
originally announced November 2000.
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Angle-resolved photoemission study of untwinned PrBa$_2$Cu$_3$O$_7$: undoped CuO$_2$ plane and doped CuO$_3$ chain
Authors:
T. Mizokawa,
C. Kim,
Z. -X. Shen,
A. Ino,
A. Fujimori,
M. Goto,
H. Eisaki,
S. Uchida,
M. Tagami,
K. Yoshida,
A. I. Rykov,
Y. Siohara,
K. Tomimoto,
S. Tajima
Abstract:
We have performed an angle-resolved photoemission study on untwinned PrBa$_2$Cu$_3$O$_7$, which has low resistivity but does not show superconductivity. We have observed a dispersive feature with a band maximum around ($π$/2,$π$/2), indicating that this band is derived from the undoped CuO$_2$ plane. We have observed another dispersive band exhibiting one-dimensional character, which we attribut…
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We have performed an angle-resolved photoemission study on untwinned PrBa$_2$Cu$_3$O$_7$, which has low resistivity but does not show superconductivity. We have observed a dispersive feature with a band maximum around ($π$/2,$π$/2), indicating that this band is derived from the undoped CuO$_2$ plane. We have observed another dispersive band exhibiting one-dimensional character, which we attribute to signals from the doped CuO$_3$ chain. The overall band dispersion of the one-dimensional band agrees with the prediction of $t-J$ model calculation with parameters relevant to cuprates except that the intensity near the Fermi level is considerably suppressed in the experiment.
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Submitted 1 August, 1999;
originally announced August 1999.