Faculty Profiles - HATA Seiichi

MoB-2-1 CHARACTERISTICS OF TI-NI-ZR THIN FILM METALLIC GLASSES FOR MEMS WITH THREE DIMENSIONAL STRUCTURE

Sakurai Junpei, Mizoshiri Mizue, Hata Seiichi

Proceedings of JSME-IIP/ASME-ISPS Joint Conference on Micromechatronics for Information and Precision Equipment : IIP/ISPS joint MIPE Vol. 2015 ( 0 ) page： _MoB-2-1-1 - _MoB-2-1-3 2015

Language：English Publisher：The Japan Society of Mechanical Engineers

We investigated characteristics of Ti-Ni-Zr thin film metallic glasses (TFMGs). The Ti-Ni-Zr amorphous thin films having Ni-content of more than 50 at.% and Zr-content of more than 11 at.% exhibited glass transition. Although the Ti_<39> Ni_<50> Zr_<11> sample had alloy composition at the boundary between TFMG and only amorphous, it showed the lowest glass transition temperature T_g of 703 K and wide width of supercooled liquid region (SCLR) ΔT of 57 K. Moreover, this sample showed a high thermal stability at the T_g . However, it is considered that viscosity of this sample was higher than those of other TFMGs

DOI： 10.1299/jsmemipe.2015._mob-2-1-1

J2220305 Flow characteristics of microvalves using Bioresist

TAKAKUWA Akira, ITO Keitaro, MIZOSHIRI Mizue, SAKURAI Junpei, ARAI Fumihito, HATA Seiiti

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2015 ( 0 ) page： _J2220305- - _J2220305- 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

We proposed a microvalve using photoprocessible thremoresponsible gel, which is called "Bioresist". Bioresist has characteristic of shrinking higher than 32 degree Celsius and swelling lower than 32 degrees. The volum change is utilized for opening and closing the microvalve. Since Bioresist is patterned, we can fabricate any arbitrary 2D shape of Bioresist using photolithography. We developed a microvalve which can control opening and closing by integrating the patterned Bioresist with a microheater using MEMS technology. The microvalve using Bioresist hasthe advantage of high speed response and low power consumption. We evaluated the relationship between applied current required for opening the microvalve and flow rate when microvalve were tested under regular pressurized flow with de-ionized (DI) water. As a result, flow rate is proportional relationship with applied current. It was shown controllability of flow rate by applied current.

DOI： 10.1299/jsmemecj.2015._j2220305-

J2220302 Evaluation of capacitance type moisture sensor with nanocrack thin film

FUKAGAWA Yuuki, SAKURAI Junpei, MIZOSHIRI Mizue, HATA Seiichi

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2015 ( 0 ) page： _J2220302- - _J2220302- 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Lubricating oil is widely used to improve performance and life of various machines. However, when amount of moisture in lubricating oil increase, lubrication performance of the lubricating oil deteriorate. It cause the trouble of the machine. Therefore, the sensor to monitor amount of moisture in lubricating oil is need. This research propose capacitance type moisture sensor that can measure the relative humidity of lubricating oil in the real time. Dielectric constant changes by moisture absorption of the dielectric of the sensor. Relative humidity can be monitored by detecting changes of capacitance. So, it is need that electrode of capacior has porous structure to facilitate moisture absorption of dielectric. In the paper, this electrode was deposited by oblique angle sputtering in high sputtering gas pressure. We defined incidence angle of sputtering particle. And we fabricated three kinds of sensors whose incidence angles of sputtering particle were respectively 90, 60, 30 degrees. Those sensors were evaluated for the relative humidity in the atmosphere using temperature and humidity testing chamber. As incidence angle decreased, hysteresis decreased. (90 deg.:12.2%F.S., 60 deg.:10.1%F.S., 30 deg.:7.2%F.S.) We considered the reason of this decrease of the hysteresis is that porosity of the electrode increased because shadow effect became remarkable.

DOI： 10.1299/jsmemecj.2015._j2220302-

J2220201 Fabrication of anti-reglection structures using self-assembled silica spheres for thermoelectric generator

KONDOU Tasuku, MIZOSHIRI Mizue, MIKAMI Masashi, SAKURAI Junpei, HATA Masashi

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2015 ( 0 ) page： _J2220201- - _J2220201- 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Thermal-photovoltaic hybrid solar generators is one candidate for energy harvesting devices. Near-infrared solar light which cannot be used for photovoltaic generator is used for thermoelectric generator. Hybrid generator with buls lens to generate temeperature gradient has been fabricated. However, it is difficult to reduce the volume of the generators due to the bulk lens. In our study, we proposed a thin-film thermoelectric generator with anti-reflection structures on the hot side of pn junctions. First, we designed the anti-reflection structures using rigorous coupled wave analysis. When the grating period was 200 nm, the reflectance exhibits minimal value of 6.7%. Anti-reflection structures was fabricated using self-assembled silica microspheres and following CuO thin film deposition. The silica microspheres were assembled by dip coating. Then, the CuO thin film were coated by reactive sputtering on the self-assembled microspheres to reduce the energy loss and to convert the solar light to thermal energy. Finally, we investigated the effect of the ant-reflection structures using a commercially-available bulk thermoelectric module. The generation voltage of the modules with anti-reflection structures was increased by comparing to the modules without the structures. This result indicates that the near-infrared solar light was efficiently absorbed and converted to the thermal energy by anti-reflection structures.

DOI： 10.1299/jsmemecj.2015._j2220201-

J2220105 Fabrication of high throughput evaluation substrate for hydrogen evolution catalyst

MIYAMATO Masashi, SUZUKI Akira, SAKURAI Junpei, MIZOSHIRI Mizue, HATA Seiichi

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2015 ( 0 ) page： _J2220105- - _J2220105- 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Electrode catalyst used in industrial electrolysis is important material which affects oxidation-reduction reaction materially. The electrode catalyst having high catalystic activity and high durability gives efficient production of chemical materials. In this study, we proposed to search for new electrode catalyst using a combinatorial method. The evaluation substrate consisting of 72 catalyst samples and 9 Pt reference electrodes was designed and fabricated by a micro electro mechanical system (MEMS) technique. The thin film electrode catalyst library on the evaluation substrate was prepared by a combinatorial multi target sputtering system using 3 pure metal targets (Ir, Ru and Ti). The alloy compositions of these thin films were measured by an energy dispersive X-ray spectroscopy. To evaluation the characteristics of catalyst samples, the polarization curves (current density/potential curves) of catalyst samples were measured by the potential sweep method. Surface poisoning and elution of catalysis samples were observed by an optical microscopy. Finally, we confirmed that the proposed combinatorial method was useful to search for new electrode catalyst materials.

DOI： 10.1299/jsmemecj.2015._j2220105-

J2220102 Fabrication of device for high throughput evaluation of magnetostriction and relative permeability

MAETANI Takuya, SAKURAI Junpei, MIZOSHIRI Mizue, HATA Seiichi

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2015 ( 0 ) page： _J2220102- - _J2220102- 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Magnetostrictive materials often used for several sensors and actuators from some features that are fast response, high power, and contactless actuation. Magnetostriction and relative permeability are important characteristics to determine the performance of the sensors and actuator, however, it need the different sample to evaluate magnetostriction and relative permeability. So that, it takes a lot of time to search new magnetostrictive materials or optimize composition of alloy magnetostrictive materials. The combinatorial method could search novel alloy materials or optimize composition efficiently compared to the conventional material searching method. In this research, we proposd the MEMS device for the combinatorial materials searching method. This device could evaluate characteristics of magnetostrictive material that are magnetostriction and relative permeability. Moreover, magnetostriction an drelative permeability are evaluated by the change of capacitance, induced electromotive force, respectively. In this paper, we show the fabrication process and fabricated device that keeps the cantilever structure.

DOI： 10.1299/jsmemecj.2015._j2220102-

J2220101 Characteristics of Ti-Ni-Cu Thin Film Metallic Glasses/Thin Film Shape Memory Alloys Before and After Crystallization

SAKURAI Junpei, MIZOSHIRI Mizue, HATA Seiichi

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2015 ( 0 ) page： _J2220101- - _J2220101- 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

In this paper, we investigated characteristics of Ti-Ni-Cu thin film metallic glasses (TFMGs)/ shape memory alloys (SMAs) for MEMS application with three dimensional structure. The Ti-poor Ti-Ni-Cu amorphous thin films (Ti content of less than 50 at.% and Cu content of more than 6 at.%) exhibited glass transition during crystallization proces and were TFMGs. Moreover, a little Ti-rich Ti-Ni-Cu (Ti-content of less than 51 at.%) samples also showed the glass transition. On the other hands when Ti content was more than 51 at.%, these samples didn't show the glass transition, irrespective of Cu content. Therefore, it is considered that the glass forming ability of Ti-Ni-Cu TFMG was better than that of the Ti-Ni-Zr TFMGs. The Ti-Ni-Cu TFMGs after crystallization at 973 K for 3.6ks showed the single martensitic transformation of B2-B19 phase upon cooling and heating. When Ti content was around 50 at.%, peak temperatures of martensitic transformation O* and A* increased with increasing Cu content until 16 at.%. Further Cu content increasing, O* and A* decreased.

DOI： 10.1299/jsmemecj.2015._j2220101-

Combinatorial search of Fe-Ni-Cr system magnetostrictive alloys for force sensors

MAETANI Takuya, NAKAMITSU Yutaka, SAKURAI Junpei, NAKAGAWA Shigeki, HATA Seiichi

Mechanical Engineering Journal Vol. 2 ( 1 ) page： 14-00462 - 14-00462 2015

Language：English Publisher：The Japan Society of Mechanical Engineers

Magnetostrictive materials of the Fe-Ni-Cr ternary system for sensitivity enhancement of force sensors were searched by using a combinatorial method. Magnetostrictive materials for force sensors require large magnetostriction, high relative permeability, and high resistivity. This research is an attempt to find composition ranges that satisfy the following requirements: magnetostriction greater than 20×10 <sup>-6</sup>, relative permeability greater than 4,000, and resistivity over 90 μΩ cm. A novel combinatorial deposition method, known as Combinatorial New Facing Targets Sputtering (Combi-NFTS) method was applied to fabricate libraries of samples with various compositions. Samples for measurement of the relative permeability and resistivity were synthesized with a composition distribution by using Combi-NFTS onto a 108 mm×76 mm glass substrate. After deposition of thin film, each sample is divided into 10 mm×10 mm. The relative permeability and resistivity were measured by using a vibrating sample magnetometer and the four probe method, respectively. Bilayer cantilever samples for evaluation of magnetostriction were fabricated onto a 6 mm×20 mm×0.1 mm Si substrate, whereby deflection of the samples changes when a magnetic field is applied. The laser lever method was used to measure the cantilever deflection. The results indicate that the composition range with an Fe content of 26-36.5 at.%, a Ni content of 61-66 at.%, and a Cr content of 7.5-9.5 at.% satisfy the requirement criteria.

DOI： 10.1299/mej.14-00462

29pm1-B-4 Fabrication of Cu2O-rich micro-temperature sensor using direct femtosecond laser reduction patterning

Itou Yasuaki, Mizoshiri Mizue, Arakane Shun, Sakurai Junpei, Hata Seiichi

The Proceedings of the Symposium on Micro-Nano Science and Technology Vol. 2015.7 ( 0 ) page： _29pm1-B-4 - _29pm1-B-4 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Micro-temperature sensors consisting of Cu_2O-rich sensing part and Cu-rich electrodes were fabricated using femtosecond laser induced reduction of CuO nanoparticles. Cu_2O-rich and Cu-rich microstructures were selectively formed by controlling laser irradiation conditions. When the laser scanning pitch was 10 μm, Cu_2O-rich microstructures were formed under the condition that the laser scanning speed and pulse energy were 1 mm/s and 0.45 nJ, respectively. Cu-rich microstructures were fabricated by the scanning speed of 10 mm/s and the pulse energy of 0.28 nJ. The Cu_2O-rich sensing part and Cu-rich electrodes were formed using the evaluated conditions. The micro-temperature sensors composed of Cu_2O-rich and Cu-rich hybrid structures were successfully obtained.

DOI： 10.1299/jsmemnm.2015.7._29pm1-b-4

S0440102 Electrical conductivity of Cu micropatterns fabricated by direct femtosecond laser reduction

Arakane Shun, MIZOSHIRI Mizue, SAKURAI Junpei, HATA Seiichi

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2015 ( 0 ) page： _S0440102- - _S0440102- 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Electrical conductivity and temperature characteristic of resistance of Cu micropatterns which were fabricated by femtosecond laser induced thermal reduction of CuO nanoparticles (NPs) was investigated. The Cu micropatterns were obtained by femtosecond laser irradiation of CuO NPs film which included CuO NPs, ethylene glycol as a reduction agent and polyvinylpyrrolidone. Composition ratio of Cu and Cu_2O of the micropatterns was evaluated by comparison of Cu/CuO and Cu_2O/CuO principal peak intensity ratios of X-ray diffraction spectra. When the scanning speed was 500 μm/s and pulse energy was 1.2 nJ, the most Cu-rich micropatterns were achieved. Besides, the temperature dependence of the resistance of Cu- and Cu_2O-rich micropatterns were evaluated. The resistance of the Cu- and Cu_2O-rich micropatterns were respectively increased and decreased with the increase of the temperature. The temperature coefficients of resistance of Cu- and Cu_2O-rich micropatterns were approximately 1.0×10^<-3>/℃ and -1.5×10^<-2>/℃, respectively. These results suggest that Cu- and Cu_2O-rich micropatterns have semiconductor and metal temperature characteristics of the resistance. This higher sensitivity of Cu_2O-rich micropatterns can be applied for micro-temperature sensors effectively.

DOI： 10.1299/jsmemecj.2015._s0440102-

S0440103 Patterning of Ni microstructures by femtosecond laser reduction of NiO nanoparticles

TAMURA Kenki, MIZOSHIRI Mizue, SAKURAI Junpei, HATA Seiichi

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2015 ( 0 ) page： _S0440103- - _S0440103- 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

We proposed fabrication process of nickel (Ni) microstructures using femtosecond laser reduction of NiO nanoparticles (NPs), and evaluated patterning properties of the Ni microstructures. In this process, NiO NP solution was prepared by mixing NiO NPs, ethylene glycol as a reducing agent, and polyvinylpyrrolidone. Then, NiO NP solution film, which was obtained by spin-coating of the NiO NP solution, was irradiated by femtosecond laser pulses in the air. As a result, NiO NPs were reduced to form Ni microstructures using thermal reaction induced by the laser irradiation. When the pulse energy was as low as 0.24 nJ, the line width was constant to be approximately 10-15 μm without depending on the laser scanning speed. This small and constant line pattern is advantageous for high resolution patterning. Crystal structure of the micropatterns was evaluated using XRD (X-ray diffraction). Maximal ratio of the XRD peak intensity of Ni to NiO was obtained under the condition that scanning speed was 1200 μm/s at pulse energy of 0.24 nJ. Using this laser irradiation condition, Ni microgear was formed. The thickness of Ni microgear was approximate 10 μm as almost equal to the NiO NP film by Field Emission Scanning Electron microscope observation. The Ni microgear enabled to be controlled by external magnetic field.

DOI： 10.1299/jsmemecj.2015._s0440103-

Study on passive momentum exchange landing gear using two-dimensional analysis

Watanabe, T; Hata, S; Otsuki, M

ACTA ASTRONAUTICA Vol. 105 ( 2 ) page： 407 - 416 2014.12

Combinatorial Search of Magnetostrictive Materials for Sensors Reviewed

Maetani Takuya, Nakamitsu Yutaka, Sakurai Junpei, Nakagawa Shigeki, Hata Seiichi

ELECTRONICS AND COMMUNICATIONS IN JAPAN Vol. 97 ( 9 ) page： 342 - U3 2014.9

Lift-off patterning of thermoelectric thick films deposited by a thermally assisted sputtering method Reviewed

Mizue Mizoshiri, Masashi Mikami, Kimihiro Ozaki, Mitsuhiro Shikida, Seiichi Hata

APPLIED PHYSICS EXPRESS Vol. 7 ( 5 ) page： 057101 2014.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We have demonstrated a patterning process for the fabrication of thermoelectric thick-film modules by a thermally assisted sputtering method (TASM) and a lift-off technique. Given the experimental requirements of TASM, poly(dimethylsiloxane) (PDMS) was used as the heat-resistant masks in the lift-off technique. After the film deposition, the PDMS lift-off mask was removed from the substrate. This process enables the fabrication of 30-mu m-thick and 300-mu m-wide Sb2Te3 and Bi2Te3 thick-film patterns. The increase in film thickness increased the power generated by the module, which was consistent with the theoretical value. (C) 2014 The Japan Society of Applied Physics

DOI： 10.7567/APEX.7.057101

Scopus

Ni-Nb-Zr-Ti amorphous alloys for glass lens molding die materials Reviewed

Shengxian Jiang, Mitsuhiro Abe, Masayuki Ando, Yuko Aono, Junpei Sakurai, Seiichi Hata

MICROELECTRONIC ENGINEERING Vol. 116 page： 6 - 10 2014.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Mold materials for glass lenses with microstructures, such as gratings, require not only excellent mechanical properties, high thermal stability and oxidation resistance, but also sufficient machinability by Single-Point Diamond Turning (SPDT). Our research on Ni-Nb-Zr alloys has shown that one amorphous alloy composition (Ni35Nb40Zr25 at.%) met almost all the requirements for glass lens mold materials. Unfortunately, when fabricating gratings on the mold, the immense wear on the bit, which may be caused by the high hardness of the alloy (more than 10 GPa by the nano-indentation method), made it impossible to cut precise gratings. Consequently, the addition of a fourth element was considered to decrease the hardness. After several experiments, the addition of Ti was found to decrease the hardness. At first, Ti was added to substitute 10% Zr, to give Ni35Nb40Zr15Ti10 at.%. Although this alloy had a lower hardness (9.5 GPa) than Ni35Nb40Zr25 at.%, it still cannot be micro-cut by SPDT. It was then decided to substitute Ti for Ni-Nb instead of Zr. Three samples: Ni30Nb35Zr25Ti10 at.%, Ni28Nb32Zr25Ti15 at.% and Ni25Nb30Zr25Ti20 at.%, were fabricated for evaluation. Finally, the Ni28Nb32Zr25Ti15 at.% and Ni25Nb30Zr25Ti20 at.% were found to have a low enough hardness to allow for precision machining. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.mee.2013.11.008

Scopus

Design of CuO anti-reflection structure for thin-film thermoelectric generator

Kondou T., Mizoshiri M., Hata S.

2014 International Symposium on Micro-NanoMechatronics and Human Science, MHS 2014 2014.1

Publisher：2014 International Symposium on Micro-NanoMechatronics and Human Science, MHS 2014

Copper oxide anti-reflection structures were designed by rigorous coupled wave analysis for thin-film thermoelectric solar generator. We proposed thin-film thermoelectric generator with the anti-reflection structure on the hot side of pn junction. When infrared solar light from 800 to 1200 nm wavelength is irradiated to the thermoelectric generator, the anti-reflection structure on the hot side generates the temperature gradient between the hot side and cold side of pn junction. When the cross-sectional geometry of the anti-reflection structures was hemisphere which was geometrically approximated pyramid one, the reflectance from 800 to 1200 nm wavelength was reduced than flat and binary ones. The reflectance of solar light was obtained by considering the solar light spectra and its polarization. By assuming that the average of TM and TE polarized light was the reflectance of solar light, the reflectance was reduced to be 9.6% when the period of the anti-reflection structure was 700 nm. Taking into account of the reflectance of Cu on cold side 99%, this large reflectance difference is expected to generate a large temperature gradient between hot side and cold side.

DOI： 10.1109/MHS.2014.7006118

Scopus

Design of CuO anti-reflection structure for thin-film thermoelectric generator Reviewed

Tasuku Kondou, Mizue Mizoshiri, Seiichi Hata

2014 INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE (MHS) 2014

Language：English Publishing type：Research paper (international conference proceedings) Publisher：IEEE

J2220203 Capacitance type moisture sensor using diagonal incidence of sputtered Cr thin film

FUKAGAWA Yuuki, MIZOSHIRI Mizue, YOSHII Yusuke, MUKAI Nobuyuki, MIZOGUCHI Takashi, TAKAHASHI Tsutomu, HATA Seiichi

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2014 ( 0 ) page： _J2220203- - _J2220203- 2014

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Performance of lubricating oil gets worse suddenly by water being mixed into oil. This causes serious failure of machine. Therefore, a sensor that monitors amount of moisture in the oil is need. In this paper, capacitance type moisture sensor is proposed for the use in lubricating oil. To realization of the sensor, upper electrode Cr was deposited as nanocrack thin film metal that separates water molecules from oil by sputtering in high sputtering gas pressure and diagonal incidence of sputtering particle. Evaluation of the sensor was conducted in the air as previous stage of evaluation in oil. The sensor proposed in this paper showed followabillity for amount of moisture in the air. Relation between sensor characteristic and sputtering condition was investigated.

DOI： 10.1299/jsmemecj.2014._j2220203-

J2220202 Combinatorial search for Fe-Ni-Cr magnetostrictive materials for sensors

MAETANI Takuya, NAKAMITSU Yutaka, SAKURAI Junpei, NAKAGAWA Shigeki, HATA Seiichi

The Proceedings of Mechanical Engineering Congress, Japan Vol. 2014 ( 0 ) page： _J2220202- - _J2220202- 2014

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

In this research, it was searched that magnetostrictive materials for sensors by using combinatorial method. Combinatorial method is the one of the useful method that could search for optical composition of alloy materials or novel alloy materials. In this method, samples having various compositions are synthesized onto a single substrate. Then, properties of each sample are evaluated efficiently. Desired value of this research is that, magnetostriction is more than 20×10^<-6>, relative permeability is more than 4000, resistivity is more than 90 μΩ・cm. Library to evaluate resistivity and relative permeability which has composition distribution was synthesized by using New Facing Targets Sputtering. Resistivity of as-sputtered sample was evaluated by using four probe method and relative permeability of annealed sample was evaluated by using vibrating sample magnetometer. Magnetostriction of annealed sample was relatively evaluated comparing to reference material. As the result, it was discovered composition area that satisfied all targeted value.

DOI： 10.1299/jsmemecj.2014._j2220202-