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Report on A-3 sessions of August 29

Matsumoto: Interesting TDGL simulations of Jc and comparison to experiment. It is reported experimental Jc measurements on BHO doped GdBCO with different level of doping. Best pinning force density Fp at 10 K was achieved on 20:1 volume fraction. The analysis of temperature behavior Jc(T) with Griessen’s model is reported.

Questions: Is the simulation 3D? No. How many pinning sites can be added to the simulation? What is the meaning of the background pins at high field? Difference of delta-l and delta-Tc pinning? How is Jc determined in the simulation?

Yoshida: SmBCO + BaHfO3 coated conductors. Low-T growth technique (750 C vs 960 C) with seed layer (150 C less than without). Rods are thinner (7 nm vs 13.5 nm), B_phi is larger. High rate leads to small pinning sites (similarly as in previous presentations).

High speed growth technique in a reel-to-reel deposition systems up to 100 Hz. No degradation of Jc reported. No clear which is the actual film growth rate.

Questions: How are the inclination angles defined? What is the effect of strain in growth of nanocolumns? What is the Ic of the sample? (from patterned sample) What is the growth rate in “high growth rate”-films?

How is the substrate temp measured? 960 C is a lot! (didn’t ask this, because of lack of time)

Erbe: ReBCO + BHO on TFA-MOD on STO and CeO2-buffered CC. Re = Gd, higher Tc, should have wider deposition parameters. Result: Narrow process parameters, otherwise impurities (on STO). On STO optimal deposition conditions are: T = 810 °C and P(O2) 100 – 50 ppm. On metal optimal t_sub is 20 C lower (we’ve seen this also on PLD films) due to the reaction with CeO2 seed layer (BaCeO3 forms). Pores in films on meta.

Questions: What about the in-plane texture? Good in-plane texture. Optimal temperature difference STO / CC. Thickness of the films: 250-300 nm.

Jha: Surface modified target approach to enhance Jc, Y211 dopant as segment of target. Nano dots formed into YBCO matrix. Jc measurements carried out at 77 and 65 K. Dip in the Jc(theta) near ab-plane. Otherwise almost isotropic. Theory from Mishec SUSt 28. Planar defects cause a dip in ab-planes. For further work doping with other rare earths RE211 phases will be studied.

Questions: Could this promote substitution of rare earth ion of dopant on superconductor? A: yes, but the final effect of this cannot be predicted in advance.

van der Beek: edge disorder and rough flux front. Flux noise in rf antennas. MO-visualization. Seen also in Nb. And in other elastic media (paper, ink on paper etc). Calculate correlations in space and time. Universality classes vary between different superconducting materials. Controlled disorder, irradiated with heavy ions.

Questions: How do the flux avalanches in MgB2 relate to this? Not really definite yet.

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Plenary 3 : Topological Quasiparticles: Magnetic Skyrmions

Axel Hoffmann, Materials Science Division, Argonne National Laboratory

In his plenary lecture Axel Hoffmann discussed new magnetically ordered structures, which recently have gained much attention due to their potential for low-energy applications.  These magnetic structures are called magnetic skyrmions and this name is derived from the theoretical physicist Tony Skyrme, who originally developed in the 1960’s a theoretical model describing nuclear particles as topological solitons within a vector field.  But similar structures can also form in magnetically ordered materials.  Interestingly, due to their distinct topology these magnetic skyrmions can behave like individual stable particles.

They were first discovered about a decade ago in special magnetic materials at low temperatures, but the work from Axel Hoffmann and his colleagues showed that they can be also stabilized at room temperature in magnetic multilayers of materials that are commonly used for magnetoelectronic applications.  At the same time these magnetic skyrmions can be easily manipulated with even very low electric currents, which makes them of interest for data storage and processing applications.

During his presentation Axel Hoffmann also showed two interesting basic physics concepts.  First he showed that magnetic skyrmions can be formed by using inhomogeneous electric currents.  This process is strikingly similar to common phenomena in surface tension driven fluid flows, such as the formation of soap bubbles by blowing through a suspended soap film.  Second he showed that the twirling magnetic structure of magnetic skyrmions results in “curved” trajectories.  The physics behind this skyrmion Hall effect is very similar to the motion of curveball in baseball or soccer, where the rotation of the ball results in a change of trajectory to confuse the batter or goalkeeper.  This shows that the investigation of magnetic skyrmions is not only fascinating because of their prospect for novel applications, but that their distinct topology also provides new interesting fundamental physical phenomena.

Axel Hoffmann always gives very interesting and valuable presentations, and his lighthearted approach, makes his talks very engaging.  Thus his Plenary Talk offered both an academic and peaceful atmosphere to audience.  As part of his Talk he presented a brief video showing how the Brazilian soccer player Roberto Carlos used a curved ball to leave the French goalkeeper confused.  This gave the audience an easy understanding for difficult physics delivered with humor.  But of course the question arises, whether “the twirling magnetic structure of magnetic skyrmions moving on curved trajectories” confused anybody?  Fortunately Axel Hoffmann addressed any remaining confusion well during the questions and answers.

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PL.2 Helical Polymers as Unique Chiral Materials Professor Eiji Yashima　(Nagoya University, Japan)

The helix is ubiquitous in nature, and one of the prevalent structural motifs for biological polymers, playing key roles in their sophisticated functions. Professor Yashima showed unique polymers consisting of preferred-handed helical conformation induced by chiral dopants.  Generally, the polymer lost preferred-handed helical structure when the chiral dopant was removed from the system.  He showed novel helical polymer which remain the preferred-handed helical structure even after removal chiral dopant using specific poly acetylene with well-established side chains.  This memory effect can be utilized for production of separation materials for chiral chemicals and drugs.

Prof. Yashima summarized helicity induction and memory strategy which has a remarkable advantage from a practical viewpoint.  Various examples on the direct observations of helical structures of synthetic helical polymers by atomic force microscopy (AFM) was presented. A series of double and/or multi helices composed of different components and sequences that exhibit specific functions, such as chiral recognition and anisotropic spring-like motion was also introduced　with very impressive images.

 

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Session C-2 Aug.29

This is the second day of C-2 session in IUMRS-ICAM2017. A first paper in the morning was cancelled. Since more than 30 audiences　were waiting in the room, Prof. Bruno Ameduri (CNRS) volunteered to entertain these audiences by his magic show. Prof. Bruno Ameduri is a famous chemist in the area of fluoropolymers and is also well known as CliniClown visiting sick children in hospitals of Montpellier and abroad. He showed the difference in molecular weight synthesized by free radical polymerization and controlled radical polymerization through the length change of three different ropes by his magic! All audiences understand the concept of molecular weight distribution of polymer.

Science magic by Prof. Bruno Ameduri

 

 

 

In the morning session, we had one contributed paper and two invited papers on stimuli responsive nanogel and polymer gel thin film were presented.  In the afternoon session, five contributed papers and five invited papers were presented.  Control of nanoparticle surface for various composite applications, structure-property relationships of novel polymer nanocomposites, and surface structure and properties of polymer ultrathin films were presented.  We have more than 50 participants and active discussion was continued until the end of the day.

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Symposium A-5 : Session OXIDES I / Aug. 29

Since an expected room change happened, the session delayed by 15 min. Except for this, the session went well successfully with forty audience.

The keynote  speaker Dr. Ryoji Funahashi presented his recent activities on new-type

thermoelectric power generators that would be able to compete costwise with other forms of power generators in future.

The second speaker Dr. Shanchela determined the effective mass of the recently developed transparent conductor BaSnO3 to be 0.4m_0.

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Symposium:B-6 Aug.29

Advances in Functions and Reliability of Ceramics and Glasses Based on Structural Formation

Solid oxide fuel cell, environmental purification filters, wind power generation and solar cells are promising advanced systems to make a contribution to energy and environmental issues. In these systems, advanced ceramics and glasses are quite important as key materials, and further improvement of the materials functions and reliability is needed. This session was planned to discuss various possibilities for the sudden rise in advanced ceramics and glasses extensively from the viewpoint of structural formation.

This session was held from Aug. 28(MON) to Aug. 30(WED), 2017, in Kyoto Univ. and had 10 invited talks, 13 oral presentations, and 24 poster presentations. The speakers came from China, Taiwan, Korea, Thailand，Mexico and Japan. There were 20 or more attendees gave enthusiastic discussion for each oral presentation from various point of view (Fig.1). Especially, on the 2nd day, Prof. Soo Wohn Lee, President of IUMRS participated this session all day and gave his comments to many presentations (Fig.2).

To advance our friendship between the speakers in this session, we went for dinner as the session banquet in the evening of the 2nd day. We enjoyed Japanese Sake and fish Hamo (Conger myriaster) in a traditional restaurant, and have a good time to know each other. We promised to meet again in the next conference when we went back our accommodations.

Finally, all the organizers greatly expressed their gratitude to all speakers of this session, and also organizing committees of IUMRS-ICAM2017.

 

Fig.1 Group Photo of B-6 session after the 1st day.

Fig.2 Group Photo of B-6 session after the 2nd day.

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Meeting scene　A-7 1st day

In the afternoon on 28th August, symposium of A-7 for next generation of fuel cell science was organized. The large room fully occupied on this date. So many participants wanted to listen the hot talk by active scientists.

1st Phot displays the lecture scene by Professor Ishihara who is authority in solid oxide fuel cell science. 2nd one shows lecture scene of Professor Nagao (Nagoya University) who discovered unique direct biomas fuel cell devices.

Also, Professor Kondo (University of Tsukuba) introduced his famous work for non-precious metal. Those invited talks paid high level attention in our symposium.

2nd day of our symposium will be started from 9 am in the South Wing room 21 of Yoshida Campus.

Look forward to seeing you in there.

Invited lecture scene by Professor Ishihara

 

 

 

Invited lecture scene by Professor Nagao

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Symposium C-2: Structure and physical properties of polymers in confined systems

The symposium C-2 started from the afternoon of August 28.  Starting from the brief introduction of scope of this symposium by organizer, we had one contributed talk and 7 invited talks regarding the dynamics of polymer chain in polymer thin films,  the microdomain structure control of block copolymers,  the structure and electronic  properties of organic thin films, and advanced multiscale simulation of polymeric solids.  We have more than 50 participants and very active discussions throughout this afternoon. We also have poster session in the evening.  30 poster papers were presented and active discussion was continued around 8pm. .  Symposium organizers  will select two ACS Langmuir Poster Awards  and one RSC Soft Matter Poster Award.  The C-2 symposium will continue until the afternoon August 30.  (by K. Kojio and A. Takahara)

Invited talk by Prof. Opelia K. C. Tsui (Hong Kong University of Science and Technology)

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PL.1 The first plenary lecture / Nobel Prize Winner, Hiroshi Amano,

The first plenary lecture was given by Nobel Prize Winner, Hiroshi Amano, Director, Center for Integrated Research of Future Electronics, and a Professor, Institute of Materials and Systems for Sustainability, Nagoya University. The Clock Tower Hall was so jam-packed there were so many standing audiences.

The title of his plenary lecture was “Development of Sustainable Smart Society via Transformative Electronics”. At the beginning of the lecture, he demonstrated the mechanism of the generation of white light using the arrays of blue LEDs with a practiced hand. He is proud that the white LEDs in conjunction with solar cells and batteries enable nomadic children of Mongolia to study nights, He emphasized the contribution of the white LED to the reduction of power consumption, His lecture was composed of three parts: AlGaN-based deep ultraviolet LEDs (DUV LED), GaN-based heterojunction field-effect transistors (HFETs) and photocathodes (or electron emitters).
According to UNICEF report in 2015, 663 million people still lack access to safe drinking water and 2.4 billion people do not use safe sanitation facilities. The high-power DUV LEDs have been utilized in commercial water sterilization and purification systems.

He compared the energy losses in photovoltaic power generation to bank transfer fees just for fun. By replacing Si-based power devices with GaN-based power devices, the average efficiency of inverters or converters can be improved from 95% to more than 99%. He said that one of his dreams is to replace the transformers used in Shinkansen train cars by the semiconductor devices completely.
In comparison with the commercial GaAs photocathodes, GaN and InGaN photocathodes have much longer lifetimes and higher quantum yields. He demonstrated that the short high-power pulsed operation is very promising for observing the blurring of moving objects.

All the audiences had a sense of the possibilities for further development of the research on the GaN based devices in the future.