Mass and generalized Thiele equation of the magnetic skyrmion

An analytical expression is obtained to the mass of an isolated magnetic skyrmion and its linearized equation of motion. The magnetic skyrmion is viewed as a topologically protected spin-wave soliton in the magnetic ultrathin films stabilized by the interfacial-Dzyaloshinskii-Moriya interaction. The equations of motion are derived from the Landau-Lifshitz-Gilbert equation for both the skyrmion charge and magnetization centers. They are generalized Thiele equations, including gyro-term, dissipation term, external force, an acceleration term with the tensorial mass, and time derivatives of the external forces. The equation of motion of the center of the skyrmion charge essentially shows the massless nature of the skyrmion. In contrast, the equation of motion for the magnetization center results in a finite mass that is in the same order as the Doring mass density for the linear domain wall. Furthermore, the time derivative of the external force predominantly contributes to the immediate response of the skyrmion motion, i.e., the mass-less property remains even after the skyrmion acquires its kinetic mass. A micromagnetic simulation based on the LLG equation was performed for various magnetic parameters. Obtained trajectories at 0 K are compared with the theoretical predictions.Comment: 28 pages, 3 figure

Manipulating 1-dimensinal skyrmion motion by external magnetic field gradient

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.Comment: 15 pages, 5 figures, 1 tabl

Examination of Color-Lighting Control System Using Colored Paper User Interface

In recent year, Full-Color LED Lighting that can be changed to various color such as red, green, blue has been appeared with development of LED Lighting. By Color-Lighting control, users affected such as concentrating and relaxing. Therefore, Color-lighting control will spread to various place such as home, offices, stations. However color-lighting control affected some disturbance such as daylight, display when Full-Color LED controlled indoors. Also, information devices control get difficult with information technology develop. I propose Color-Lighting Control System using Colored Paper User Interface(CLC/CPUI). The purpose of CLC/CPUI is that anyone can intuitively control Full-Color LED Lighting. CLC/CPUI uses colored paper as user interface by sensing the paper. CLC/CPUI realizes lighting color that user demanded to do feedback control. I conduct accuracy verification experiment of CLC/CPUI

Examination of Color-Lighting Control System Using Colored Paper User Interface

In recent year, Full-Color LED Lighting that can be changed to various color such as red, green, blue has been appeared with development of LED Lighting. By Color-Lighting control, users affected such as concentrating and relaxing. Therefore, Color-lighting control will spread to various place such as home, offices, stations. However color-lighting control affected some disturbance such as daylight, display when Full-Color LED controlled indoors. Also, information devices control get difficult with information technology develop. I propose Color-Lighting Control System using Colored Paper User Interface(CLC/CPUI). The purpose of CLC/CPUI is that anyone can intuitively control Full-Color LED Lighting. CLC/CPUI uses colored paper as user interface by sensing the paper. CLC/CPUI realizes lighting color that user demanded to do feedback control. I conduct accuracy verification experiment of CLC/CPUI

Brownian Motion of Magnetic Skyrmions in One- and Two-Dimensional Systems

Magnetic skyrmions, which are topologically protected particle-like spin textures, exhibit Brownian motion at ambient temperatures in a ferromagnetic thin film. The potential applications of a skyrmions' diffusive motion to the ultra-low energy stochastic and Brownian computation make research on its thermal dynamics necessary. Herein we experimentally demonstrate the mobility anomaly of the diffusion coefficients in one-dimensional diffusion processes. In addition, we observed a chiral property in the velocity-position correlation functions. The results are discussed in the context of Brownian motion in the shallow potential fluctuations. The data indicate the importance of the chiral property of skyrmions in Brownian motion. ©2021 The Physical Society of Japan1

Association of TNFRSF4 gene polymorphisms with essential hypertension

This is a non-final version of an article published in final form in Mashimo, Yoichi ; Suzuki, Yoichi ; Hatori, Kazuko ; Tabara, Yasuharu ; Miki, Tetsuro ; Tokunaga, Katsushi ; Katsuya, Tomohiro ; Ogihara, Toshio ; Yamada, Michiko ; Takahashi, Norio ; Makita, Yoshio ; Nakayama, Tomohiro ; Soma, Masayoshi ; Hirawa, Nobuhito ; Umemura, Satoshi ; Ohkubo, Takayoshi ; Imai, Yutaka ; Hata, Akira, Association of TNFRSF4 gene polymorphisms with essential hypertension, Journal of Hypertension, 26(5) May 2008, pp. 902-913 autho

Skyrmion Brownian circuit implemented in continuous ferromagnetic thin film

International audienceThe fabrication of a circuit capable of stabilizing skyrmions is important for the realization of micro- to nano-sized skyrmion devices.Ultralow power Brownian computers have been theoretically proposed and are a promising example of a skyrmion-based device. However,such devices have not been realized as it would require skyrmions to be stabilized and easily movable within a circuit. Skyrmion circuitsfabricated by the etching of ferromagnetic films often decrease the dipolar magnetic field stabilizing the skyrmions, thus preventing theirformation. In this study, a skyrmion Brownian circuit has been implemented in a continuous ferromagnetic film with patterned SiO2 cappingto stabilize the skyrmion formation. The patterned SiO2 capping controls the saturation field of the ferromagnetic layer and forms awire-shaped skyrmion potential well, which stabilizes skyrmion formation in the circuit. Moreover, using this patterned SiO2 capping, we haveimplemented a Y-junction hub circuit exhibiting no pinning site at the junction, contrary to conventional etched hubs. Thus, this techniqueenables the efficient control of skyrmion-based memory and logic devices to move closer toward the realization of Brownian computers

TRIC-A Channels in Vascular Smooth Muscle Contribute to Blood Pressure Maintenance.

小胞体カウンターイオンチャネルTRICチャネルによる血圧調節機構とTRICチャネル遺伝子多型による本態性高血圧リスク. 京都大学プレスリリース. 2011-08-02.TRIC channel subtypes, namely TRIC-A and TRIC-B, are intracellular monovalent cation channels postulated to mediate counter-ion movements facilitating physiological Ca(2+) release from internal stores. Tric-a-knockout mice developed hypertension during the daytime due to enhanced myogenic tone in resistance arteries. There are two Ca(2+) release mechanisms in vascular smooth muscle cells (VSMCs); incidental opening of ryanodine receptors (RyRs) generates local Ca(2+) sparks to induce hyperpolarization, while agonist-induced activation of inositol trisphosphate receptors (IP(3)Rs) evokes global Ca(2+) transients causing contraction. Tric-a gene ablation inhibited RyR-mediated hyperpolarization signaling to stimulate voltage-dependent Ca(2+) influx, and adversely enhanced IP(3)R-mediated Ca(2+) transients by overloading Ca(2+) stores in VSMCs. Moreover, association analysis identified single-nucleotide polymorphisms (SNPs) around the human TRIC-A gene that increase hypertension risk and restrict the efficiency of antihypertensive drugs. Therefore, TRIC-A channels contribute to maintaining blood pressure, while TRIC-A SNPs could provide biomarkers for constitutional diagnosis and personalized medical treatment of essential hypertension