Superconduction " Xiaoshi is acting " : Pressure hill is big more superconductive_News

Pressure just can have power, dynamical ability insists to progress.

-- Lei Feng

Pressure, it is a kind of mystical force. Scientists think, the origin of earthly life, the high pressure that comes from extremely likely in ocean heats up a spring. Earthly interior, scroll is worn the lava of high temperature high pressure, formation ground magnetic field lets life spare the harm of high-energy universe ray. In material science, pressure is material of a kind of efficient synthesis and adjusting control the important step of its content sex. Pressure can let material produce a lot of magical change, for instance black a black lead, below high temperature high pressure, become the diamond that shows glaring eye likely. So, the friends of loving diamond should wake up to reality, likewise carbolic atom forms it and black lead, rare not at all. Nowadays, diamond of complex of this kind of artificial technology, enough achieves 11 carat above, look and natural diamond difference is not big, also depend on merely with the distinction of black lead " pressure hill is big " just (graph 1) .

Superconduction " Xiaoshi is acting " : Pressure hill is big more superconductive

Graph 1 " pressure hill is big " black lead old father became diamond

In superconductive data research, high pressure is very important method. Below high pressure, mutual contact is close together between raw material, response rate should be more than chemistry to often press a case far, improved the efficiency of material preparation greatly. Commonly used high pressure synthesizes a method to have a lot of, for instance high pressure of many top high temperature is synthesized and synthesis of high-pressured reaction boiler. Former more complex, outer it is a ball carapace, pass press medium to lapping 8 balls inside control hammering block, carry on 6 tops on the head to control hammering block next, press on one to be passed tetrahedrally again control medium, most inside just be sample material (graph 2) . The layer upon layer pressure of such design is delivered, can comparing the implementation in narrow space finally hundred thousands of atmosphere (~20 GPa) . High pressure reacts boiler suits fluid photograph synthesis quite, put raw material in the liquid and its high pressure is sealed, the pressure after temperature is elevatory will be higher, the growth that is helpful for certain sample (graph 2) . High pressure of high temperature of have the aid of, can realize many material that often press next cannotting get. To certain and special material, be like compound of a few basket shape, in often press fall to stabilize existence hard or synthesize. Wrap up is worn methane the basket shape hydrate that wait, say again for " can light ice " , namely high pressure falls in ocean form. The complex below a few high pressure material of superconduction of basket shape structure, be like Ba8Si46 material, critical temperature is 3) of 8 K(graph about. The stuff with the very expensive hardness such as a lot of boride, also need synthesis of high pressure of have the aid of to finish.

Graph citing of device of synthesis of 2 high pressure (come from English Vicki 100 divisions)

Graph 3 " basket shape " superconductor Ba8Si46(comes from Hiroi.issp.u-tokyo.ac.jp)

In exploration of high temperature superconduction, synthesis of high temperature high pressure is divine arms edge tool likewise. Tie Jichao guides material is in at the beginning of 2008 after discovery, it is in brief number week, critical temperature promoted 55 K from 26 K, those who lean is complex of high temperature high pressure efficient with high quality ReFeAsO1-xFx(Re=La, ce, pr, nd, sm... ) sample. Material of cupreous oxide superconduction is likewise OK synthesis of high pressure of high temperature of have the aid of, for example Ca2CuO2Cl2 needs high-pressured complex one kind namely superconductor of cupreous oxide high temperature, its structure and the structure of La2-xBaxCuO4(214 of cupreous oxide superconductor that discover the earliest) very similar, latter matrix is La2CuO4. Recently, of the group of Jin Changqing research of institute of physics of the Chinese Academy of Sciences and Japanese Tokyo university inside Tian Shen is first-class cooperate, came true to be the Ba2CuO4- δ material of 214 structures likewise below high temperature high pressure, critical temperature is as high as 4(a)) of 73 K(graph. This means superconductor of high critical temperature, may not needs element of have the aid of to replace adulteration to come true certainly. And the group of research of tiger famous the sea of Nanjing university, criterion the cupreous oxide superconductor that high pressure of high temperature of have the aid of synthesized lukewarm area of a kind of liquid nitrogen successfully (Cu, c)Ba2Ca3Cu4O11+ δ (Tc=116 K) , δ of GdBa2Ca3Cu4O10+ of material of superconduction of another kind of when discovered similar structure on this foundation new high temperature or GdBa2Ca2Cu3O8+ δ (δ of Tc=113 K) , GdBa2Ca5Cu6O14+ (Tc=82 K) (graph 4(b)) . This kind of material and have the HgBa2Ca2Cu3O8+ δ that often approachs records of next highest and critical temperature (Hg-1223 system, tc=133 K) system has similar structure, but do not have noxiousness, and have first-rate superconduction application parameter.

Graph complex of 4 high pressure is new-style cupreous oxide superconductor (come from Arxiv.org)

With complex of high temperature high pressure " congenital " high-pressured photograph is compared, "Posteriority " high pressure is OK also the feature of material of adjusting control superconduction, especially critical temperature. Later period adds high-pressured method to have a lot of, those who have maximum pressure of similar high temperature is much face a top to control hammering block (~30 GPa) , the maximum pressure that also has piston cylinder structure is wrapped (~2 GPa) , the freeboard pressure that still instantaneous explosion is released (~1000 GPa) . The most commonly used is diamond " control hammering block to the top " : With two diamond of most advanced abrasive supports to press sample to the top, pressure of highest static state can achieve millions atmosphere (~400 GPa) . Interesting is, diamond is its the strongest hardness to carrying those who press anvil to lean on the head, what use for the most part is making synthetic diamond of complex of high temperature high pressure, because purity wants tall and the price is not quite expensive. Those who use diamond is pervious to light and characteristic, can introduce electromagnetism radiate (wait like X ray) come the real pressure that demarcate material gets, or the spectrum that measures material is characteristic (graph 5) . Measure as to electricity or magnetics, need alone and derivative measure down-lead or adscititious coil, difficulty also is very big.

Graph the 5 high pressure that are based on diamond to control hammering block to the top are measured (come from English Vicki 100 divisions)

To superconductor of high temperature of major copper oxide, high pressure often is helpful for promoting Tc, use maximum pressure for instance, the critical temperature of Hg-1223 system can raise 164 K further, it is the high temperature superconductor of be worthy of the name. Then, on the journey that in contend superconduction critical temperature records, the content sex below high pressure is measured, become " perfect " tweak. To not superconductive material, pressure, superconductive perhaps. To already superconductive material, pressure, critical perhaps temperature rose. To high temperature superconductor, press again, probably critical temperature breaks through a record. Some scientists are certain even: "No matter any material, want pressure sufficient get at only, it is met superconduction! " scientists are taking pressure this tool, swept periodic chart almost, discover a large number of is in to often control next not superconductive metalloid elements, be OK below high pressure superconductive. And to tantalum, high pressure issues Tc of possible farther promotion, among them highest is Ca simple substance, 6) of Tc=29 K(graph falls in 216 GPa.

Graph superconductor of simple substance of 6 tall depressive (come from Www.spring8.or.jp)

Why the effect with so breathtaking to exceeding conductivity to you can be obtained high pressure? The reason has a lot of. Think roughly to have at 3 o'clock: Reduced material bulk to increase electronic concentration at the same time, make material produced structural photograph to change those who promoted new superconductive look form, great some kind of interaction that increased to be helpful for superconduction. Below high pressure, gas can compress a liquid, the liquid compresses solid further, solid is compressed again, likely translate into metal. Theoretic think, the smallest element on the world -- hydrogen, be in enough below high pressure, can turn a metal into hydrogen. And, because of hydrogenous nucleus substantially with respect to a proton, once form metallic hydrogen, the energy of atomic hot vibration is very tremendous, enough lets an electron, the superconductor that high critical temperature forms below phonon coupling, it is room temperature superconductor even. Metallic hydrogen, it is superconductive investigator people one of dreams. Realize metallic hydrogen, not be a simple thing. Pure want a gaseous state and the hydric outfit that explodes extremely easily is opposite into diamond inside top anvil and do not run, it is challenge of a technology. Real operation is the hydrogen that loads liquid state below microtherm, use force again next. Fluid hydrogen boiling point is controlled in 20 K, the operation rises to have difficulty very much. The pressure that realizes metallic hydrogen also is very tremendous, egghead predicts at first need 100GPa, namely million atmosphere, consider as 400 GPa above later. But this tries experimental physicist, 80 pass more. 2016, e of British Edinburgh university. One kind when the person such as Gregoryanz obtained hydrogen in 325 GPa " new solid state " , think the likelihood is metallic hydrogen. 2017, the United States breaths out the R of Buddha university. Dias and I. F. Two people of Silvera announce metallic hydrogen comes true, in the solid of transparent hydrogen element below 205 GPa, turn into to 415 GPa the semiconductor hydrogen with opaque black, the metallic hydrogen that becomes metallic sex finally to glance to 495 GPa (graph 7) . Unfortunate is, when them preparation measures a metal when whether hydrogen has sex of report of room temperature superconduction, a not careful operation error, the diamond that pressing metallic hydrogen is right go to sticks and staves carrying anvil on the head, metallic hydrogen also disappears into thin air. Up to now, people still repeats an experiment to obtain hydrogen of metal of so tall depressive hard, and metallic hydrogen whether room temperature superconductor, remain a mystery!

Graph hydrogen of metal of 7 tall depressive (come from Www.latimes.com)

The way that seeks superconduction of metallic hydrogen room temperature is full of challenge and twist, the research group that this experiment can be competent to work on international is very few also. Scientist think better of thinks, want dead to staring at simple substance hydrogen to death for what? If look for hydrogenous compound, whether to realize the superconduction below high pressure possibly also? If really as expected, on December 1, 2014, german mark Si Pulang overcomes the scientist A of chemical institute. P. Drozdov and M. I.Eremets announces to discover 190 K superconduction in vulcanization hydrogen 0 resistor phenomenon, pressure is 150 GPa. This numerical value broke through Hg-1223 to hold old 164 K record, the be inspired with enthusiasm that did not arouse superconductive academia however -- Wu Long incident is troubled by the superconduction of USO room temperature that they are appeared again and again already tiredly to be able to 't bear, to the thing of record-breaking the first reaction is doubt. Wait for a person in Eremets even for many times in academic report, the assembly room quizs to be done not have almost, a lot of people are held wait-and-see with distrustful manner. All previous classics 8 many months, in ceaseless doubt, investigation, repeat the experiment, painful torment that gathers more data to fall, the paper was published at Nature on August 17, 2015 eventually, the Tc that right now they had obtained the 203 K below 220 GPa and the corresponding signal that fight magnetism, achieved superconductive history new record (graph 8) . The occurrence of incident of vulcanization hydrogen superconduction, let contain smelly egg originally the material of special odour, became the new heat of superconductive academia. After through the many research of Japan, United States, China the group repeats experimental result, the superconductive ability of vulcanization hydrogen be able to authentic, everybody thinks generally " only then the person that make tomb figure " it is H3S, not be that provoking the smelly egg gas of be disgusted with. If you still are written down, this 1:3Structure, it is photograph of so called A15, wait for structural just the same with Nb3Sn, Nb3Ge, Nb3Al! In fact, german scientist also is not is sudden inspiration, got the theory of Chinese scientist is calculated however enlightenment. Vulcanization hydrogen is superconductive below high pressure itself is not curious, be based on an electron, the BCS theory of phonon coupling predicted the high temperature of metallic hydrogen is superconductive, superconduction of hydride high pressure also is extremely possible. 2014, the superconductive report sex that the group of research of equestrian Yan inscription of Chinese Jilin university predicts H2S has 80 K to control in 1.6 million atmosphere first, study group of fatidical H2S-H2 compound to come true possibly below high pressure with the Cui Tian that is in Jilin university 191, the high temperature of 204 K is superconductive. German experiment discovers 70, the photograph of superconduction of relatively inferior temperature of 90 K, mix 170, the photograph of high temperature superconduction of 203 K, with two theory works is to happen to have the same view simply. Chinese scientists predicted object height of more hydrogen sulfide presses the existence of high temperature superconductor likewise, for example CaH6, GaH3, SnH4, Si2H6, PH3. In August 2018, same research group announces a Germany LaHx superconductive Tc is 215 K(150 GPa) , back-to-back move announces the another research group such as American Washington university LaHx superconduction Tc can be amounted to 260, 280 K(190 GPa) . This new result still still waits for more experiments to confirm, no matter how, the room temperature that is apart from 300 K is superconductive, already stretched his hand it seems that can reach.

Graph superconduction of hydrogen of the vulcanization below 8 superhigh pressure (come from Www.nature.com and Mappingignorance.org)

Want to realize room temperature superconduction, still can use " assorted fist " . In May 2018, one of the scientist of Germany and England's top to critical temperature groovy superconduction, k3C60, bring to bear on high pressure while introduce infra-red light to cause instantaneous superconduction, the critical temperature of extremely brief life breaks through 9) of 300 K(graph completely possibly. If these results are exact word, can say, room temperature superconduction had come true. Excited when also did not forget to sprinkle cold water of one gourd ladle, because of the superconduction of such superhigh pressure or transient state, to superconduction application, it is the anguish like disaster. Have a kind to resemble " Afanda " in the film in that way " ore of superconduction of natural room temperature " ? Not be to be impossible. If arrive deep the gaseous planet with the oldest solar system -- go in Jupiter, below the pressure that can discover Jupiter interior is as high as 400 GPa, formed metallic hydrogen or hydrogenous compound extremely likely (graph 10) . Because many silicon alkyl is contained in Jupiter gas (SiH4-H2) , the ore of room temperature superconduction in fokelore, did not hide over definitely, see you have skill to sent disinter to come.

Graph 9 K3C60 causes superconductive appearance solely in tall depressive (come from Www.nature.com)

Graph structure of 10 Jupiter interior (come from Www.britannica.com)

Finally, of ambitious attune is, pressure hill always is not advantageous to superconduction greatly. High pressure is occasionally harmful instead, its meeting suppress destroys superconduction even, the most serious is a material complete have one's body smashed to pieces, again also cannot superconduction. Below high pressure, because basically measure a method centrally for report, if form other superconduction miscellaneous photograph or certain a few foreign matter high pressure are superconductive, metropolis influence arrives measure conclusion. The multiple test method such as magnetism, hot, light repeats a test with many groups, it is very necessary. The birth that any new high pressure superconduction record, suggest everybody is in hopeful while, withhold cautious attitude continuously.

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