Tohoku University. Research Profiles

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"S" Keywords - 167 Result(s)

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[Spintoronics]

Electrical Spin Generation and Manipulation in Semiconductors

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Since spin orbit interactions caused by the structural inversion asymmetry and the bulk inversion asymmetry induce an effective magnetic field in III-Vsemiconductor heterostructures, it is possible to realize the new functional devices based on the electrical control of the spin precession. We study the electrical spin generation by using spatial modulation of spin orbit interaction, which demonstrates Stern-Gerlach spin filter in semiconductors, and research ultra-fast spin dynamics by using time resolved Kerr rotation microscopy. We also investigate a spin MOSFET based on the perpendicular magnetic materials and electric-field induced magnetization control. We can reduce the leak current and the signal delay in the logic circuit. With the non-volatility of the ferromagnetic source and drain electrodes, random access memory is also enabled by using the spin MOSFET structure.

Targeted Application(s)/Industry

Target application will be low power logic devices and non-volatile memory based on electron spins and also future metal-based spintronic devices.

Department of Materials Science, Graduate School of Engineering
KOHDA, Makoto, Associate Professor Doctor of Engineering

[Spintronics]

Fabrication of Spintronics Materials by Artificial Nanostructure Control

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Our group works on the fabrication of materials and the fundamental study of physical phenomena for spintronics. Particularly, we are interested in magnetic ordered alloys, and fabricate nanolayered structures, tunnel junctions or composite device structures with those materials to investigate novel magnetic and magnetotransport properties. Recently we are also interested in the correlation between spin and heat currents, and investigate novel thermo-electric phenomena.

Targeted Application(s)/Industry

We hope to conduct collaborative research with a willing company for a practical application of new spintronic devices with low energy consumption and thermoelectric devices for energy harvesting.

Institute for Materials Research
TAKANASHI, Koki, Professor Doctor of Science

Novel-Concept Silicon Integrated Circuits Derived from the 3-Dimensional Device, Circuit and Architecture

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In recent year, facing the age of nanoscale engineering, the new technologies of device, circuit and architecture supported by novel physical guidance principles are highly expected, just as the similar situation as the predawn of semiconductor technology when Bardeen and Shockley discovered the secret of transistors. Therefore, in our research approach, the architectures, circuits, devices and CAD design tools for nanoscale LSI are systematically investigated in the following three main research subjects.
1. Study on nanoscale device and circuit
Aiming at the nanoscale silicon semiconductor integrated circuit, we are mainly working on the following directions for new devices and circuits:
①Analysis for novel physical phenomenon based on nanostructural effects
②Device and circuit technology with new operating principle
③Restraint technology for increasing variability of device characteristics
④Architecture and circuit technology for robust information processing
2. Study on the 3-dimention-structual device and circuit
The elementary element of recent LSI with planar-structural devices is coming close to the physical limitation of scaling. In order to break the limit and sustain the evolution of future LSI performance, we have started the research on the novel 3-dimension-structural devices and circuits.
3. research on wireless integrated circuit (IC) based on information transmission
The ultracompact lightweight wireless IC is one of essential technologies for realizing the ubiquitous society which has the network available in anywhere, at anytime and from any surrounding items. For example, the IC tags for receiving information with reading function are getting close to the practical applications. In our laboratory, aiming at the automatic operating wireless IC with embedded power supply, we are systematically working on the following directions:
①The electrical power generation and storage devices
②Devices and circuits with Ultralow power consumption
③Sensing devices
For all above subjects, We hope to conduct collaborative researches with companies interested in our research.

Targeted Application(s)/Industry

Center for Innovative Integrated Electronic Systems
ENDOH, Tetsuo, Professor Doctor of Engineering

Theoretical Design of New Materials and Device Functionality based on First-principles Calculations

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We are doing theoretical research on electrical conductivity in magnetoresistive devices using highly spin-polarized materials. The aim is to achieve very functional spintronics devices such as read-out heads for ultrahigh-density magnetic recording and non-volatile spin memories. We also investigate magnetoresistive devices using perpendicularly magnetized materials to ensure endurance against thermal fluctuations of the magnetization. We successfully achieve a guideline for improvement of the magnetoresistive performance by designing the crystal structure at the interface between ferromagnets and oxides theoretically.
We believe that first-principles calculations, which need no empirical parameter, play a very important role in research and development of various materials. Please contact us if you want to collaborate with us.

Research Institute of Electrical Communication
SHIRAI, Masafumi, Professor Doctor of Engineering

Development of High Sensitive Magnetic Sensor Operating at Room Temperature with Tunnel Magnetoresistance Devices

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Recently, many tunnel magnetoresistance devices with high magnetoresistance effect are reported. These are expected to be applied to high sensitive magnetic sensors. There are many magnetic sensors with variety of the mechanism, in order to meet the demand of the very wide range of sensing magnetic field. However, there is no magnetic sensor which has high sensitivity, easy to use, operation at room temperature and low cost. Only a magnetic sensor with tunnel magnetoresistance devices can satisfy all the demand in principle. As the device has very wide range of the sensing magnetic field, it can be designed for any demand to the sensors.

Targeted Application(s)/Industry

For example, this device can sense a bio-magnetic field easily at room temperature, so that it could be replaced SQUID device, which is popular now but is very expensive and not easy to use personally. Therefore, by using this device, we expect we can conduct effective collaborative research in medical field.

Department of Applied Physics, Graduate School of Engineering
ANDO, Yasuo, Professor Doctor of Engineering

Spintronics Devices and Materials

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Spintronics is a technology utilizing electron spin which provided magnetic sensor, nonvolatile magnetic memory, and so on. Our studies are as below.

Noble & Rare-earth free magnetic films with large perpendicular magnetic anisotropy. We achieved to develop various Mn-bases alloy films exhibiting high perpendicular magnetic anisotropy (Fig.1 ).
THz range observation of magnetization motion. We achieved to detect a motion of magnetization using pulse laser in time domain (Fig. 2).
Novel organic spin devices. We achieved to fabricate hybrid junction consisting of an organic layer sandwiched by two inorganic magnetic layers and to observe magnetoresistance effect.
Tunnel Magnetoresistive devices: We are developing TMR devices with Mn-Ga alloys films (Fig.3 ).

Targeted Application(s)/Industry

Magnetic memory and storage. Microwave and Terahertz wave. Magnetic sensors.
We hope to conduct collaborative research with a willing company for a practical application of these devices and materials in industry.

WPI Advanced Institute for Materials Research
MIZUKAMI, Shigemi, Professor Doctor of Engineering

[Spintronics device]

Spintronics device

Features

To realize ultralow-power and high-performance integrated circuit and information processing, spintronics physics, material, devices are studied.

Research Institute of Electrical Communication
FUKAMI, Shunsuke, Associate Professor Doctor of Engineering

[Spintronics integrated circuits]

International industry-academic consortium (CIES consortium) enhances creation of innovative integrated electronic technologies from material/process/LSI to software/tool/system (Center for Innovative Integrated Electronic Systems: CIES)

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Integrated electronic systems are a fundamental technology that makes possible the lifestyles of ease and abundance we enjoy in the modern world. By leveraging innovative core technologies and longstanding accomplishments of industry-academic cooperation in Tohoku University as centripetal forces, we have promoted the CIES Consortium consisting of industry–academic collaborations, major national projects and community-based cooperation projects in the fields of Spintronics, AI hardware and Power Electronics through our cooperation with a diverse range of Japanese and foreign companies from fields such as materials, equipment, devices, circuits and systems. CIES has promoted world level Academic-Industrial Collaboration under establishment of world-first 300mm wafer process line and facilities for prototype manufacturing and characterizing spintronics integrated circuits compatible with world-class companies in university campus.

Targeted Application(s)/Industry

CIES has conducted international industry-academic collaboration in the fields of integrated electronic technologies ranging from materials/equipment to devices/systems. In addition, we have promoted to cooperate with regional and local companies with support of local government (Miyagi Prefecture, Sendai City, Iwate Prefecture, etc) for contributing to Tohoku reconstruction and regional development. We welcome your participation in CIES consortium.

Center for Innovative Integrated Electronic Systems
ENDOH, Tetsuo, Professor Doctor of Engineering

[SR motor]

Research on High Performance Motor and its Applications

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Electric motors are essential devices in all areas such as industrial, traffic and civilian use. The demand of the electric motors is rising each year. In order to realize a high performance electric motor, we study the following items:
1. Development of a motor simulation method for accurate and fast calculation.
2. Considerations on an optimum control method of motors.
3. Application of the electric motor to an electric vehicle.
4. Regeneration and application of rotating mechanical energy.
The features of our study are a simulation method based on magnetic circuit model, SR motor without permanent magnet, and in wheel direct drive electric vehicle.

Targeted Application(s)/Industry

As we have basic skill for a magnetic field analysis, electric and electronic circuit analysis and control technic, our targeted applications are improvement of permanent magnet motor, SR motor and its applications to an electric vehicle and various mobilities. Small size generator is also our targeted application.

Graduate School of Engneering
ICHINOKURA, Osamu, Professor Doctor of Enginering

[State analysis]

Development of new methods and apparatus for industrial elemental analysis

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A goal of our research is to develop new instrumental methods in quantitative elemental analysis. We have suggested a new analytical method enabling trace elements at a few ppm level to be directly determined. We now study analytical applications of a low-pressure laser induced plasma as well as a glow discharge plasma associated with laser ablation, in order to carry out rapid analysis for the process control in material industries and for selection of scrapped materials.

Targeted Application(s)/Industry

Industry: We have already conducted cooperative research on industrial analyses with several metal-making companies as well as the iron and steel institute of Japan. We also hope cooperative works on practical analysis in various manufacturing fields.

Institute for Materials Research
WAGATSUMA, Kazuaki, Professor Doctor Eng.

[Statistical Mechanics]

Optimizing everything / Optimal Society

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Aiming at developing practical quantum optimization technology known as quantum annealing, we are working on exploring basic technologies that can overcome the limitations and applications in collaboration with multiple companies. The advantage of the method is that it can be used simply by formulating a cost function that draws the goal to be optimized once, but we are not limited to the original method. We extend it by considering a much easier problem, sequential optimization by learning, black box optimization, etc.. In particular, it is being applied to automated driving, logistics in factories, and evacuation guidance during disasters.

Targeted Application(s)/Industry

Applications to route search problems such as automatic driving of various vehicles, evacuation route guidance at the time of disaster, process scheduling and a large number of combination problems. We can provide a solution to combinatorial optimization in each industry. (Transportation / distribution, manufacturing, materials, drug discovery, etc.)

Graduate School of Information Sciences, Applied Information Sciences, Information and Applied Technology, Physical Fluctuomatics
OHZEKI, Masayuki, Associate Professor Doctor of Science

[Statistical Science]

Data Analytics for Creation of Social Values

Features

My research field is a data analytics for creation of social values by data science approaches. In modern society, we can observe various data sets about our daily life, business or community. I aim to create new services for it using such data set and methods of Bayesian modeling, data mining or machine learning.

Targeted Application(s)/Industry

Graduate School of Economics and Management
ISHIGAKI, Tsukasa, Associate Professor Doctor of Philosophy

[Steel Moment Resisting Frames]

[Steelmaking]

Composition and Structure Control of Steel and Other Metals Using Refining and Solidification

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The production processes of base materials, such as iron- and steel-making processes, belong to an age of technical innovation toward an eco-friendly society. To support this innovation, fundamental studies are being conducted in our laboratory. The main subjects are "Process Design of Highly Efficient Reactors by Enlargement of Reaction Interface", "Recovery of Rice Field damaged by Tsunami using Steelmaking Slag", "Recovery of Rare Metals from By-product of Steelmaking Process", and "Control of Non-metallic Inclusions on Clean Steel Production".

Targeted Application(s)/Industry

Directly we are carrying out the collaboration with steelmaking companies, however, our technology can be applied to non-ferrous production and recycling process using high temperature treatment.

Institute of Multidisciplinary Research for Advanced Materials
KITAMURA, Shinya, Professor Doctor of Engineering

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[stainless steel]

Suppression of Intergranular Degradation of Polycrystalline Materials by Grain Boundary Engineering

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Intergranular degradation often results in decreased lifetime, reliability and economical efficiency of polycrystalline materials. In spite of persistent efforts to prevent such degradation, its complete suppression has not yet been achieved. Grain boundary studies have revealed that coincidence-site-lattice (CSL) boundaries have stronger resistance to intergranular degradations than random boundaries. The concept of ‘grain boundary design and control' has been refined as grain boundary engineering (GBE). GBEed materials which are characterized by high frequencies of CSL boundaries are resistant to intergranular degradations. Our group has achieved very high frequencies of CSL boundaries in commercial stainless steels by GBE. GBEed stainless steels showed significantly stronger resistance to intergranular corrosion (see Figs. 1 and 2), weld-decay, knife-line attack, stress corrosion cracking, liquid-metal embrittlement, radiation damage, etc. and much longer creep life (see Fig. 3) than the unGBEed ones.

Targeted Application(s)/Industry

By using this GBE processing, we expect to conduct effective collaborative research in related fields.

Department of Materials Processing, Graduate School of Engineering
SATO, Yutaka, Professor Ph.D.

Development of the Nickel-Free Dental Magnetic Attachment Using the Magnetic Shielding Material which Lost its Magnetism by Nitrogen-Solid Solution

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In the dental magnetic attachments which retain dentures, superstructures of dental implants, and so on, the non-magnetic stainless steel containing nickel is used in order to reinforce their retentive force by a magnetic circuit. The surface layer of magnetic stainless steel which loses its magnetism by nitrogen-solid solution obtained from heating in nitrogen gas at high temperature, enable to form a magnetic circuit, which does not contain nickel at all, and to reduce its components and manufacturing processes. The method using the nitrogen-solid solution in this study is warrantable to manufacture the nickel-free dental magnetic attachment with high safety.

Targeted Application(s)/Industry

The nickel-free magnetic attachment realizes a retainer with higher safety, and can expect the application to medical and dental care for clinical uses, such as not only a denture but a dental implant, an epithese, and so on with easy desorption.

Division of Dental Biomaterials, Graduate School of Dentistry
TAKADA, Yukyo, Associate Professor Doctor of Engineering

[statistics]

[steel]

Advanced Control of Microstructure and Property of Structural Metallic Materials

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Microstructure represents various kinds of heterogeneities in the metallic materials, i.e., grains, component phase, lattice defects and chemical inhomogeneity such as impurity/alloying elements. It can be modified through control of phase transformation/precipitation and deformation/recrystallization by adjusting compositions of materials and/or through processing routes (heat treatment, deformation). Such expertise in micro/nanostructure control is very important in production of current materials from viewpoints of energy saving and recycling in structural materials such as steels and titanium alloys.
We attempt to apply more advanced control of micro/nanostructures, such as atomic structures of crystalline interfaces, chemistory in an atomic scale (e.g., segregation) and so on. Fundamentals of microstructure formation (thermodynamics, kinetics, crystallography) are examined both theoretically and experimentally to clarify key factors for microstructure control. Another important aspect in our research is the improvement of mechanical property by microstructure manipulation.

Targeted Application(s)/Industry

Possibilities to establish new functions (e.g., superplasticity, shape memory/superelasticity) as well as superior mechanical properties (e.g., ultrahigh strength with high toughness/ductility) is also explored.

Institute for Materials Research
FURUHARA, Tadashi, Professor PhD

[stent]

Biomodel for Development of Endovascular Treatment

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We perform in-vitro or computational researches for development of medical devices. We develop a model of artery or bone to evaluate medical devices. And we apply optimization way for development of medical devices. Our main target is, currently, stent, or catheter.

Targeted Application(s)/Industry

Our collaboration company can be; medical equipment, device, medical image, MEMS, standardization, medical training, or polymer.

Institute of Fluid Science
OHTA, Makoto, Professor Doctor of Engineering

[step length]

Assessment of Physical Activities Using Wearable Sensors

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Maintaining appropriate amount of physical activity is essential for health and disease prevention. Gait is the most common type of physical activity in everyday life. Monitoring the amount of physical activity in everyday lives may benefit mainly those who are at threat of metabolic syndrome and overweight. Towards better estimation of the amount of physical activity utilizing wearable sensors, we focused on taking running and walking economy into account. The relationship between step length and oxygen uptake was first determined. Step length estimation with moderate accuracy was accomplished using acceleration signals during walking. Step length was then taken into energy expenditure calculation as one of the variables.

Targeted Application(s)/Industry

Together with the basic version of the current locomotion monitoring system capable of counting staircase climbing up & down, we managed to upgrade our locomotion monitoring system into 3 dimensional.

Graduate School of Biomedical Engineering
NAGATOMI, Ryoichi, Professor