Intelligence Monthly of Shanghai Superconductor

Sep. 2015

■The new Institute of Physics discovered a new high-temperature superconducting phase in LaOFeAs

■Hefei Institute of Physical Science completed heat treatment for superconducting outsert coils of hybrid magnet

■Ad Astra Rocket Company and National Aeronautics and Space Administration completed thecontract negotiation

■3-Cs successfully deposited superconducting materials on the cylindercontinuously and seamlessly

■American Superconductor gave a financial report of the first quarter in the fiscal year of 2015

■HTS-LLObuilt a high-temperature superconducting vector magnet for University of Otago

■Mainz University began to manufacturesuperconducting RF modules

■The electrified system of Japan’s passenger transport line passed the test successfully

■The good situation of expanding the scale of photovoltaic power station by 30% in 2015will probably last for five years

■China vigorously developed smart grid and cable industry, showing anexplosive growth

Civil Status

Institute of Physics discovered a new high-temperature superconducting phase in LaOFeAs

According to the report on the official website of Chinese Academy of Sciences on 29 Sep.,researchers fromInstitute of Physics, Chinese Academy of Sciences/ Beijing National Laboratory of Condensed Matter Physics (preparation) discovered a new high-temperature superconducting phase iniron-based materials keeping away from antiferromagnetic order. Moreover, the maximum superconducting transition temperatureTc exceeds the superconducting phase of the same matter nearmagnetic order, reaching 41K (defined according to resistivity data).

The iron-basedcompound superconductor was found by HosonoResearch Group of Tokyo Institute of Technology in 2008. Its parent materialLaFeAsO has a phase of antiferromagnetic order. Afterfluorine elements are used to replace some oxygen elements, themagnetic order is restrained and thesuperconducting state appears. Thesuperconducting transition temperatureTc changes with the doping contentx of fluorine, forming a vaulted superconducting area; x can reach 0.2 only. When x = 0.06, Tc of the sample reaches the maximum value which is 27 K. At this time, very strong low-energy spin fluctuations exist. This naturally makes people believe that thesuperconducting state in iron-based superconductor is caused by spin fluctuations.

Recently, Associate ResearcherYang Jie et al. from Institute of Physics, Chinese Academy of Sciences / SC9 Group ofState Key Superconductor Laboratoryof Beijing National Laboratory of Condensed Matter Physics (preparation) cooperated with Academician Zhao Zhongxian and Li Jianqi Research Group of Chinese Academy of Sciences, to synthetizea series ofhighly dopedsamples of LaFeAsO1-xFx via the high-pressure sample preparation technique. The doping contentx can reach 0.75, far exceeding people’s cognition. Through the measurement on resistivity, magnetic susceptibility and nuclear magnetic resonance, it is found that the superconducting transition temperatureTc will form a new superconducting area with x. Under the optimumdoping content (x = 0.5-0.55), Tc is even higher than the original value under x = 0.06 (Tc defined according to resistivity and resistance data is 41K. Tc defined according to magnetic susceptibility is 30 K).

It’s even more surprising that in this new-foundsuperconducting area, thephysical properties are totally different from the first superconducting area reported previously. Firstly, according tothe1/T1T measurement of NMRspin-lattice relaxation rate, no trace of spin fluctuations exists. Secondly, according to NMR and electron microscope, a new type of structural phase transition exists in the samples. During phase transition, thequadruplerotational symmetry is damaged. The variation curve ofphase transitiontemperature with doping content can extend to the optimumdoping. Meanwhile, resistivity presents a lineartemperature change near the optimumdoping, indicating a new quantum fluctuation.

This implies that high-temperature superconductor might be an extremely universalphenomenon. Besides spin fluctuations discussed by people during recent 30 years, othermechanisms like orbital fluctuations might also trigger high-temperature superconductor. This achievement has provided a brand-newclue for the exploration of high-temperature superconductor. This research result is published on Chin. Phys. Lett., 32, 107401 (2015) in the form of Express.

This research has obtained supports from “973” Project of Ministry of Science and Technology, Class-B Pilot Project of Chinese Academy of Sciences, and National Natural Science Foundation.

Phase diagram of LaFeAsO1-xFx. AF, SCI and SCII represent antiferromagnetic area, superconducting area I and superconducting area II respectively. Thesuperconducting transition temperatureTc is decided by the magnetic susceptibility; the structural phase transitiontemperatureTs and Xs are decided by the NMRexperiment and electron microscope experiment.

Hefei Institute of Physical Science completed heat treatment for superconducting outsert coils of hybrid magnet

According to the news of Hefei Institute of Physical Science on 17 Sep., the 40-Teslaclasshybrid magnet of SHMFF is composed of internal water-coolingmagnet and externalsuperconducting magnet. Many technological problems are involved in the design and development of externalsuperconducting magnet, and heat treatment technology is an important link. On 15 Sep., High-Intensity Magnetic Field Center of Hefei Institute of Physical Science, Chinese Academy of Sciences completed heat treatmentfor all coils of externalsuperconducting magnet, and final assembly of the 40-Teslaclasshybrid magnet will be carried out comprehensively.

Thecoil of externalsuperconducting magnet is composed of seven coils which are A, B and C as well as D1, D2, D3 and D4respectively. Afterexperiencing a series of links covering cable stranding, poling and enwinding in the early stage, it will enter the link of heat treatment. According to the design requirements, heat treatment should be conducted for six times, and 22 to 25 days are needed every time. The whole heat treatment work was started on 12 Jan. 2015 and ended on 15 Sep. 2015, lasting for 8 months. According to the test on annealed samples, key indexes of coils, like critical current density and remaining resistivity value, have reached the design requirementsduring all heat treatment processes.

Heat treatment is conducted to realize mutual diffusion of niobium andtin in braided wirematerials, and to generate a chemical reaction. The ultimate goal is to produce the Nb3Sn compound superconductor. Theheat treatmentresult of Nb3Sn materials will finally decide the performance of superconducting magnet, so it is a key job to decide the success of superconducting magnet project. This job will lay a foundation for the next step of externalsuperconducting magnet, and provide a solid foundation for the completion of hybrid magnet.

Heat treatment for coil D is completed

Global View

Ad Astra Rocket Company and National Aeronautics and Space Administration completed thecontract negotiation

According to the report of Superconductor Week on 17 Aug., Ad Astra Rocket Company and National Aeronautics and Space Administrationsuccessfully completed contract negotiation about the Next Step award. Moreover, this project has entered theexecution phase. This contract is a three-year agreement of fixed price, and its total value exceeds 9 million dollars. Thestructure of this agreement is a one-year contract plus two one-year extension contracts. It is a milestone based on both parties’ mutual recognition.

Background of the event: During this period, Ad Astra Rocket Company will comprehensively develop a VASIMRengine of updated version with flight conditions. Under a high-intensity magnetic field, such as the magnetic field generated by superconducting magnet, ions will rotate at a fixedfrequency. The VASIMRion engine has taken full advantage of this principle, to make the second-stage rocketheations with 1million degrees. Thistemperature is equivalent to the temperature of the solar core. Thus, high thrust will be produced.

3-Cs successfully deposited superconducting materials on the cylinder continuously and seamlessly

According to the report of Superconductor Week on 17 Aug., Malvern3-CsCompanysuccessfully deposited the YBCO layerof high-temperature superconducting materialon thehastelloybase band around the cylinder wallcontinuously and seamlessly via the method of pulsed laser deposition. This event represents the breakthrough of preparation for cylindricalcoated conductors, and the company has developed this technology for more than ten years.

The cylindricalcoated conductor is a totally different method to realize the production of electric devices based on high-temperature superconducting coated conductors. As a result, the original technology of winding superconducting strips into coils is replaced by thin film deposition and photolithography of directly using multi-layer superconducting coils on the cylindricalsubstrate. University of Birmingham has already cooperated with 3-Cs to develop coated conductor technology for multiple years.

3-Cssuccessfully depositedYBCO on the stripsubstrate surface with a width of 1cm around the cylindercontinuously, and induced a continuouslarge current to flow past this cylinder. At present, the size of cylinder adopted by 3-Cs can hold 7 strips with a width of 1cm. Meanwhile, the number of layers can change with different applications of every strip. Only one layer is needed for many applications to magnetic shielding strips.

PLD adopted the deposition method of preferential development. The whole process is compatible with different production methods of initial texture layer, including ISD and IBAD. After trial operationofISD for many years, 3-Cstends to conduct deposition on the initialhigh-qualitytexture layer produced by iBeam Material Company. This company was founded by Vladimir Matias who once worked in Los Alamos National Laboratory. Meanwhile, there are many other differentdeposition methods applied to the follow-up texture buffer layer and YBCO layer. 3-Cs tends to use PLD.

American Superconductor gave a financial report of the first quarter in the fiscal year of 2015

According to the report of Superconductor Week on 17 Aug., American Superconductor declared that its income of the first quarter in the fiscal year of 2015 increased by 102.6%, rising from 11.7 million dollars in the first quarter of 2014 to 23.7 million dollars. Its net loss of Generally Accepted Accounting Principles decreased from 13.5million dollars to 9.1 million dollars. The company’s sales volumes in wind power technology and superconducting power grid technology fields also increase. Theshare price of American Superconductor decreased from 4.95 dollars to 4.39 dollars by 11.3% on the day of issuing the financial report.

HTS-LLO built a high-temperature superconducting vector magnet for University of Otago

According to the report of Superconductor Week on 17 Aug., HTS-LLO has successfully entrusted thesuperconductingelectromagnet project to University of Otago in New Zealand. This magnet is the company’s first three-axis vectormagnet (a type of magnetic field and the orientation can be taken in all directions). This magnet is the company’s first three-axis vectormagnet, and the magnetic field can point to any direction. After operating to the maximum power, main coil of the magnet will produce a vertical z-axismagnet of 0.3 Tesla, and the auxiliarycoil will generatex-axis and y-axis of 10milli Tesla. Swivel adjustment can be realized for the direction of main field, to match theaxial direction of the sample. Though the auxiliary field is very small, the coil producing auxiliary field has already approached the limit of carrying capacity.

Mainz University began to manufacture superconducting RF modules for the energy recoverysuperconducting accelerator of Mainz

According to the report of Superconductor Week on 17 Aug., a team of JGU has started to manufacture two superconducting acceleratormodules for the electron accelerator planned, energy recovery superconducting accelerator (MESA) of Mainz. MESA will contain the accelerator technology of energy recoverylinear accelerator (ERL), which will recycle some energy applied to thebeam of accelerated electrons, thus the operating cost can be reduced. Members of the project team includeRIengineers, physicists and manufacturing specialists from Nuclear Physics Institute and Manufacturing Company of JGU.

Professor Kurt Aulenbacher from Nuclear Physics Institute of JGU said, “In an ERL, theenergy of electron beams is increased to 105MEV in theRF superconducting cavity. Therefore, thebeam power with the electric current of 10 mA in MESA can reach 1megawatt.”After the experiment, this electron beam will slow down in the cavity. Hence, the kinetic energy of electrons will be recovered and stored in theRF superconducting cavityas RF energy to accelerate the follow-up beam of particles. The recovery efficiency during speed reduction, including wasted energy in the test, exceeds 99%. However, the electron beam cannot slow down to zero, and it still retains the energy of 50kilowatts in the RF system. In order to operate theMESA, liquid helium and wall socket with the power consumption of about 1 megawatt need to be set as supports. Without energy recovery, the numerical valuewould be tripled. For a bigger facility, saving will be more obvious.

News In Brief

The electrified system of Japan’s passenger transport line passed the test successfully

Recent news: RTRI reported that the application of superconducting wires to the elevatedelectrified system for passenger transport linepassed the test successfully. This test was conducted on the line with a direct voltage of 1.5kV. This is a passenger transport line on IzuRailway with a length of 20km, leading to Shuzenji. Thesuperconducting wire (cooled to about 77K) was used to connect AC-DCtransformers in the transformer substation of tractive power supply system.

Seatitan superconducting fan of American Superconductor

Recent news: Via the technology of marine propulsion motor in thenavy project of America and leading technology in superconducting field, the output power of Seatitan fan generatorsettechnology of American Superconductor can double the maximum output power of existing wind driven generators in theory, reaching 10MW. The high-temperature superconducting direct drive motor with a diameter of about 5m and weight of about 160t will be the key to success of this project. Comparatively speaking, under the same output power, the diameter of permanent magnetic direct drive motors should reach 10m and the weight must exceed 200 t. A wind turbine generator with big rated power can reduce the generating cost for unit megawatt in the completed wind field, and the power density of superconducting wind driven generator can realize a high-power and economic wind turbine generator.

Meanwhile, AMSC declared that attention was paid to theSeatitan system of 10MW at present, but it was feasible to design a draught fan of 20MW with high-temperaturesuperconducting technology.

Concept map for Seatitansuperconducting fan

SUPRAPOWER under the joint leadership of 3TechnaliaKarisruhe

Recent news: The research target of SUPRAPOWERsubsidized by European Union is to developwind energy via superconductor. Nine partners from industrial and scientific research fields have participated in this project. Technical Institute of Physics of KIT will build a rotarycryostat for this project. The Gifford – McMahonradiator will be utilized to cool the superconducting coil to -253.15degrees Celsiusthrough pure heat conduction. Under this temperature, thesuperconductor has no resistance phenomenon, and losslesselectric conduction can be realized.

Lexusexhibited a superconductinghoverboard recently

Recent news: Recently, Lexusexhibited a superconducting hoverboard, named “slide” in Barcelona. The professional skateboarderRoss McGourantested this device in a track of 220 meters equipped with magnets. Magnetic levitation technique was adopted for the sliding block: the insulatingsuperconducting core moved above the magnetic field. Cooledliquidnitrogen was embedded into the cryostat, to cool the plate to 76 K. This plate remained electrified for about 20 minutes, till evaporation of theliquid nitrogen. This project was started with the cooperation between scientists from evico and Leibniz Institute of Solid Materials (IFW) 18 months ago.

The sliding platevideo uploaded by this company and played for several months has triggered a hot discussion. Lexus clearly expressed that this slide was anunannouncedautomobile marketinggimmick, and could not be used for commercial purposes. This sliding plate is the fourth project in the promotion activity of “Amazing in Motion” organized by Lexus.

The good situation of expanding the scale of photovoltaic power station by 30% in 2015will probably last for five years

Recent news: On 28 Sep., National Energy Administration issued Notification on the Expansion ofPhotovoltaic Power Station Construction Scale in Some Regions in 2015 (hereinafter referred to as Notification). It requires thestate to increase the photovoltaic power stationconstruction scale by 5.3 million kilowatts. Compared with the target of 17.8 million kilowatts for the whole year established previous, the scale has been increased by 30%. It is even doubled when compared with last year.

Such good situation will probably last for five years in the future. According to the journalist’s data, competent departments of the state are studying the “13th Five-Year Plan”. Three associations of photovoltaic industry in China have jointly submitted a policy about photovoltaic industry development. They suggest that the generation target should be increased. It is generally expected that the photovoltaic installation scale on the market will increase from 100GW to 150GW. Therefore, the industry prosperity will turn better continuously.

According to the data, an installed photovoltaic power generation capacity of 7.73 million kilowatts was added in the first half of this year, completing 43% of the full-year targetwhich is 17.8 million kilowatts. Theinstalled capacity of photovoltaic power station was increased by 6.69 million kilowatts, and the distributed photovoltaic capacity was increased by 1.04 million kilowatts. According to the accumulativeinstalled power-generating capacity, the target established for the “12th Five-Year Plan”of solar energyhas been completed in advance.

However, the problem of power generation absorption still exists. In the first half of this year, about 1.8 billion KWHs of electricity were discarded, which mainly happened in Gansu and Xinjiang. In Gansu Province, 1.14 billion KWHs of electricity were discarded, showing a discarding rate of 28%. In Xinjiang (including Xinjiang Corps), 541 million KWHs of electricity were discarded, showing a discarding rate of 19%. “We have to abandon many electric powers as they cannot be transmitted. Therefore, the problem of electric transmission should be solved first in the ‘13th Five-Year Plan’,” said MengXiangan (Vice Chairman of Chinese Renewable Energy Society).

China vigorously developed smart grid and cable industry, showing an explosive growth

Recent news: National Development and Reform Commission and National Power Bureau issued a definite opinion to advance the development of smart power gridsa few days ago. Theyput forward that a secure and reliable, open and compatible, two-way and interactive, efficient and economic, and clean and environmentalsmart grid system should be completed by the beginning of 2020.