At present, scientists around the world are trying to find new superconducting materials, do you know the benefits and uses of superconducting materials?

In 1911, the Dutch scientist Ones (Ones) used liquid helium to cool mercury, when the temperature dropped to 4.2K, the resistance of mercury completely disappeared, this phenomenon is known as superconductivity, this temperature is called the critical temperature. Depending on the critical temperature, superconducting materials can be categorized into high-temperature superconducting materials and low-temperature superconducting materials. However, the "high temperature" mentioned here is still far below the freezing point of 0°C, which is an extremely low temperature for the average person.In 1933, two scientists, Meissner and Oxenfeld, discovered that if a superconductor is placed in a magnetic field and cooled down, the magnetic induction lines will be discharged from the superconductor at the same time as the material's electrical resistance disappears and cannot pass through the superconductor, which is known as antimagnetic properties. After the efforts of scientists, the magnetoelectric barrier of superconducting materials has been crossed, the next hurdle is to break through the temperature barrier, that is, the search for high-temperature superconducting materials. In 1973, a superconducting alloy, niobium-germanium alloy, was discovered with a critical superconducting temperature of 23.2K, a record that has been held for nearly 13 years. In 1986, the U.S.-based IBM research center in Zurich, Switzerland, reported an oxide (lanthanum-barium-copper oxide) with a high-temperature superconductivity of 35K. Since then, scientists have been coming up with new research results almost every few days. In 1986, the superconducting material researched by Bell Laboratories in the United States, its critical superconducting temperature reached 40K, liquid hydrogen's "temperature barrier" (40K) was crossed. In 1987, the United States Chinese scientists Zhu Jingwu and Chinese scientists Zhao Zhongxian successively in the yttrium-barium-copper-oxygen system of materials to increase the critical superconducting temperature to more than 90K, liquid nitrogen's "temperature barrier" (77K) was also broken. At the end of 1987, thallium-barium-calcium-copper-oxygen materials raised the critical superconducting temperature to 125 K. In just over a year from 1986 to 1987, the critical superconducting temperature was raised by nearly 100 K. From 1986 to 1987, the critical superconducting temperature was raised by more than 100 K. The critical superconducting temperature was raised by more than 100 K. temperature was raised by almost 100 K. Using neutron scattering techniques, scientists from Germany, France, and Russia observed the so-called magnetic **** vibration mode in a member of the high-temperature superconductors, the single copper-oxygen layer Tl2Ba2CuO6 + δ, which further confirms the generality of the existence of such modes in high-temperature superconductors. The finding contributes to the study of the mechanism of copper oxide superconductors. High-temperature superconductors have higher superconducting transition temperatures (typically higher than the temperature at which nitrogen is liquefied), which is conducive to the widespread use of superconducting phenomena in industry. It has been 16 years since the discovery of high-temperature superconductors, but the study of their many features and their microscopic mechanisms, which are different from those of conventional superconductors, is still at a rather "rudimentary" stage. This is reflected not only in the absence of a single theory that can fully describe and explain the properties of high-temperature superconductors, but also in the lack of a unified "intrinsic" experimental phenomenon that is common to all different systems. The results reported in this issue of Science imply that a long-standing puzzle in the field of neutron scattering is likely to be resolved. Back in 1991, French physicists used neutron scattering to detect a weak magnetic signal in a single crystal of the double copper-oxide-layered YBa2Cu3O6+δ superconductor. Subsequent experiments demonstrated that this signal is significantly enhanced only when the superconductor is in a superconducting state and is referred to as a magnetic **** vibration mode. This finding suggests that the spins of the electrons cooperate in some way to produce a collective, ordered motion that is not present in conventional superconductors. It is possible that this collective motion is involved in the pairing of electrons and is responsible for the superconducting mechanism, which acts in a similar way to the lattice vibrations that cause the pairing of electrons within conventional superconductors. However, the same phenomenon could not be observed in another superconductor, La2-xSrxCuO4 + δ (single copper-oxygen layer). This led physicists to suspect that this magnetic **** vibration pattern is not a common phenomenon in copper oxide superconductors.In 1999, this magnetic **** vibration signal was also observed in Bi2Sr2CaCu2O8 + δ single crystals. However, since Bi2Sr2CaCu2O8+δ, like YBa2Cu3O6+δ, also has a double copper-oxide layer structure, the confusion about whether the magnetic *** vibration pattern is a special characterization of the double copper-oxide layer or a "universal" phenomenon has not been resolved completely. The ideal candidate would be a typical high-temperature superconducting crystal with as simple a structure as possible, having only a single CuOx layer. The difficulty lies in the fact that only crystals large enough for neutron scattering experiments are possible due to the weak interaction of neutrons with matter. As neutron scattering techniques have matured, the requirements for crystal size have been reduced to the order of 0.1 cm3. Advances in crystal growth techniques have also brought the size of Tl2Ba2CuO6 + δ single crystals into the millimeter scale, for which it is an ideal candidate. Scientists arranged 300 millimeter-scale Tl2Ba2CuO6+δ single crystals in the same standard crystallographic orientation to form a "man-made" single crystal, "in advance" to meet the requirements of neutron scattering. After nearly two months of collecting scattering spectra and repeatedly verifying them, we have finally obtained conclusive experimental data showing that the magnetic **** vibration mode also exists in such a nearly ideal high-temperature superconducting single crystal. This result indicates that the magnetic *** vibration mode is a general phenomenon of high-temperature superconductivity. The absence of magnetic *** vibration modes in the La2-xSrxCuO4+δ system is an exception to the "universal" phenomenon, which may be related to its structural peculiarities. Theoretical and experimental studies of magnetic *** vibration modes and their interactions with electrons have been one of the hot topics in the field of high-temperature superconductivity, and the above results will attract the attention and interest of many physicists. The 1980s was a golden age for the exploration and study of superconductivity. 1981 saw the synthesis of organic superconductors, and 1986 saw the discovery by Müller and Bernolds of LaBaCuO4, a ceramic metal oxide composed of barium, lanthanum, copper, and oxygen, with a critical temperature of about 35 K. Since ceramic metal oxides are usually insulating substances, the discovery was of great significance and was rewarded with the 19th Annual Award of the Nobel Prize in Physics for the discovery of the ceramic metal oxide, which is the most important of all the superconducting materials. Bernolds were awarded the 1987 Nobel Prize in Physics for this discovery. In 1987, there was a new breakthrough in the exploration of superconducting materials, the University of Houston physicist Zhu Jingwu's group and the Institute of Physics of the Chinese Academy of Sciences, Zhao Zhongxian and others successively developed into a critical temperature of about 90K superconducting material YBCO (yttrium bismuth copper oxide). In early 1988, Japan developed into a critical temperature of 110K Bi-Sr-Ca-Cu-O superconductor. Thus, mankind has finally realized the dream of liquid nitrogen temperature zone superconductor, a major breakthrough in the history of science. These superconductors are called high-temperature superconductors because their critical temperature is above the liquid nitrogen temperature (77 K). Since the discovery of high-temperature superconductors, a wave of superconductivity fever has swept the world. Scientists have also found that thallium-based superconductors have a critical temperature of 125 K, and mercury-based superconductors have a critical temperature of 135 K. If mercury is subjected to high pressure, its critical temperature can reach an incredible 164 K. In 1997, researchers discovered that gold-indium alloys are both superconductors and magnets near absolute zero. 1999 scientists discovered that a ruthenium-copper compound is superconductive at 45K. Because of its unique crystal structure, the compound's potential for use in computer data storage is enormous. Since December 2007, Dr. Genfu Chen of the Institute of Physics, Chinese Academy of Sciences, has been involved in the preparation of lanthanum-oxo-iron arsenic undoped single crystals. On February 18 this year, Professor Hideo Hosono of the Tokyo Institute of Technology and his collaborators published a two-page article in the Journal of the American Chemical Society, pointing out that fluorine-doped lanthanum-oxoferric arsenic compounds at minus 247.15 degrees Celsius that is superconductivity. Researchers Chen Genfu and Wang Nanlin, who have maintained a habit of cross-border attention in their long-term research, immediately captured the value of this news, and Wang Nanlin's group quickly turned to making doped samples, and they achieved superconductivity and measured the basic physical properties within a week. Almost simultaneously, Haihu Wen's group at the Institute of Physics found superconductivity with a critical temperature of -248.15 degrees Celsius or more by replacing trivalent lanthanum with divalent strontium metal in lanthanum-oxygen-iron arsenic materials. March 25 and March 26, the University of Science and Technology of China Chen Xianhui group and the Institute of Physics Wang Nanlin group respectively independent discovery of the critical temperature of more than minus 233.15 degrees Celsius of superconductors, breakthrough McMillan limit, confirmed as a non-traditional superconductivity. March 29, academician of the Chinese Academy of Sciences, Institute of Physics researcher Zhao Zhongxian led the group through the fluorine-doped praseodymium oxygen iron arsenic compound superconducting critical temperature of up to minus 221.15 degrees Celsius, in early April, the group found that non-fluorine anoxic samarium oxygen iron arsenic compound synthesized in a pressure environment superconducting critical temperature can be further increased to minus 218.15 degrees Celsius. In order to confirm (superconductor) resistance is zero, scientists will be a lead ring, into the temperature below Tc = 7.2K space, the use of electromagnetic induction so that the ring to stimulate the induction current. The results found that the ring current can continue, from March 16, 1954, to the beginning of September 5, 1956 end, in two and a half years the current has not decayed, which shows that the ring within the electrical energy is not lost, when the temperature rises to higher than the Tc, the ring from the superconducting state into a normal state, the resistance of the material suddenly increased, the induced current immediately disappeared, which is the famous Ones persistent current experiments. 1.superconducting technology talk 1911, Leiden University, the Netherlands, Kammerling Onnes accidentally found that the mercury cooling to -268.98 ° C, the resistance of mercury suddenly disappeared; later he found that many metals and alloys have with the above mercury is similar to the loss of resistance at low temperatures of the characteristics of the special conductive properties, due to its conductive properties, Kammerling Onnes called superconducting state. Kammerling was awarded the Nobel Prize in 1913 for his discovery. This discovery caused a worldwide shock. After him, people began to call conductors in the superconducting state "superconductors". The DC resistivity of superconductors suddenly disappears at a certain low temperature, which is called the zero resistance effect. With no resistance in the conductor, there is no heat loss when the current flows through the superconductor, and the current can flow through the wire without resistance, thus generating a super-strong magnetic field. In 1933, the Netherlands, Meissner and Osenfeld *** with the discovery of another superconductor is extremely important properties, when the metal is in a superconducting state, the superconductor within the magnetic susceptibility of the strength of zero, but the original existence of the body of the magnetic field crowded out. Single-crystal tin ball experiment found that: the transition to the superconducting state of tin ball, tin ball around the magnetic field suddenly changed, the magnetic line of force seems to be excluded to the superconductor outside all of a sudden to go, people will be this phenomenon is called "Meissner effect". Later, people also did such an experiment: in a shallow flat tin plate, put a small volume but the magnetic force is very strong permanent magnet, and then reduce the temperature, so that the tin plate superconductivity, then you can see, the small magnet even left the surface of the tin plate, slowly floating up, hanging in the air. Meissner effect has an important significance, it can be used to determine whether the substance has the super nature. In order to make superconducting materials have practicality, people began to explore the course of high-temperature superconductivity, from 1911 to 1986, the superconducting temperature from mercury 4.2K to 23.22K (OK = -273 ° C). 86 January found that barium lanthanum copper oxide superconducting temperature is 30 degrees, December 30, and will refresh this record for 40.2K, 87 January rose to 43K, and soon and rose to 46K and 53K, February 15, 98K superconductors were found, and soon found signs of superconductivity at 14 ° C, high-temperature superconductors have made a huge breakthrough in superconductivity technology to large-scale applications. Superconducting materials and superconducting technology have broad application prospects. The Meissner effect in superconductivity phenomenon allows people to use this principle to create superconducting trains and superconducting ships, because these vehicles will run in a frictionless state, which will greatly improve their speed and quiet performance. The superconducting train has been successfully tested for manned feasibility in the 70's, and since 1987, Japan has been running trials, but they often fail, probably due to the bumps generated by high speeds. Superconducting ship has been launched on January 27, 1992 test voyage, has not yet entered the practical stage. The use of superconducting materials to create transportation in the technical obstacles still exist, but it is bound to trigger a wave of transportation revolution. The zero resistance properties of superconducting materials can be used for power transmission and the manufacture of large magnets. Ultra-high-voltage power transmission can have significant losses, while the use of superconductors minimizes losses, but the adoption of superconducting power transmission is limited by the fact that superconductors with higher critical temperatures have not yet entered the practical stage. With the development of technology and the emergence of new superconducting materials, the hope of superconducting power transmission can be realized in the near future. Existing high-temperature superconductors are still in a state where they must be cooled with liquid nitrogen, but it is still considered one of the greatest discoveries of the 20th century. 2. superconductivity technology and its applications Bill Lee In 1911, the Dutch scientist Onnes cooled mercury with liquid helium, when the temperature dropped to 4.2K when the mercury resistance was found to disappear completely, a phenomenon known as superconductivity. 1933, Meissner and Oxenfeld two scientists found that if the superconductor is placed in a magnetic field to cool it down, then at the same time as the resistance of the material disappeared, the magnetic induction line will be discharged from the superconductor, can not pass through the superconductor, the superconductor. discharged and cannot pass through the superconductor, a phenomenon known as antimagnetism. Superconductivity and antimagnetism are two important properties of superconductors. The temperature at which the resistance of a superconductor becomes zero is called the critical temperature of superconductivity. After decades of efforts by scientists, the magneto-electric barrier for superconducting materials has been crossed, and the next hurdle is to break through the temperature barrier, i.e., to seek high-temperature superconducting materials. Exotic superconducting ceramics In 1973, a superconducting alloy, niobium-germanium alloy, was discovered, with a critical superconducting temperature of 23.2K, a record that has been held for 13 years. 1986, the U.S. IBM research center based in Zurich, Switzerland, reported that an oxide (lanthanum - barium -copper-oxygen) with 35K high-temperature superconductivity, breaking the traditional "oxide ceramics is an insulator" concept, causing a sensation in the world of science. Since then, scientists are scrambling to attack, almost every few days, there are new research results. At the end of 1986, the U.S. Bell Labs research oxide superconducting materials, its critical superconducting temperature of 40K, liquid hydrogen "temperature barrier" (40K) was crossed. 1987 February, the U.S. Chinese scientists Zhu Jingwu and Chinese scientists Zhao Zhongxian in yttrium-barium-copper-oxygen materials. -In February 1987, American Chinese scientist Zhu Jingwu and Chinese scientist Zhao Zhongxian successively raised the critical superconducting temperature to more than 90K on yttrium-barium-copper-oxygen materials, and the forbidden zone of liquid nitrogen (77K) was also miraculously broken through. -oxygen materials and the critical superconducting temperature record to 125 K. From 1986-1987 in just over a year's time, the critical superconducting temperature was increased by more than 100 K, which in the history of materials development, and even in the history of scientific and technological development can be called a major miracle! The continuous introduction of high-temperature superconducting materials has paved the way for superconducting materials from the laboratory to application. Supergroup of superconducting magnets The most attractive applications of superconducting materials are power generation, power transmission and energy storage. Since superconducting materials have zero resistance and are completely antimagnetic in the superconducting state, a steady state strong magnetic field of more than 100,000 gauss can be obtained by consuming only a very small amount of electrical energy. In contrast, to produce such a large magnetic field with a conventional conductor as a magnet would require a huge investment of 3.5 megawatts of electrical energy and a large amount of cooling water. Superconducting magnets can be used to make AC superconducting generators, magnetic fluid generators and superconducting transmission lines. Superconducting generator In the field of electric power, the use of superconducting coil magnets can be used to increase the magnetic field strength of the generator to 50,000 to 60,000 gauss, and there is almost no energy loss, this generator is the AC superconducting generator. Superconducting generator single generator capacity than conventional generators to increase 5 to 10 times, up to 10,000 megawatts, while the volume is reduced by 1/2, the weight of the machine is reduced by 1/3, power generation efficiency increased by 50%. Magneto-fluid generator Magneto-fluid generator is also inseparable from the help of superconducting strong magnets. Magnetic fluid power generation, is the use of high temperature conductive gas (plasma) as a conductor, and high speed through the magnetic field strength of 50,000 ~ 60,000 gauss strong magnetic field and power generation. The structure of the magnetic fluid generator is very simple, and the high-temperature conductive gas used for magnetic fluid power generation can also be reused. Superconducting Transmission Lines Superconducting materials can also be used to make superconducting wires and superconducting transformers, so that electricity can be delivered to users almost without loss. According to statistics, the current copper or aluminum wire transmission, about 15% of the power loss in the transmission line, just in China, the annual power loss of more than 100 billion degrees. If changed to superconducting power transmission, the power saved is equivalent to dozens of new large-scale power plants. Wide range of superconducting applications The use of high-temperature superconducting materials is very broad, can be roughly divided into three categories: high-current applications (strong electrical applications), electronics applications (weak electrical applications) and antimagnetic applications. High-current applications that is the aforementioned superconducting power generation, transmission and energy storage; electronics applications, including superconducting computers, superconducting antennas, superconducting microwave devices, etc.; antimagnetic mainly used in the magnetic levitation trains and thermonuclear fusion reactors. Superconducting magnetic levitation train Using the antimagnetism of superconducting materials, superconducting materials are placed on top of a piece of permanent magnet, and since the magnetic lines of force of the magnet cannot pass through the superconductor, repulsive forces will be generated between the magnet and the superconductor, causing the superconductor to levitate above the magnet. This magnetic levitation effect can be utilized to create a high-speed superconducting magnetic levitation train. Superconducting computers High-speed computers require a dense arrangement of components and connecting wires on an integrated circuit chip, but the densely arranged circuits generate a large amount of heat when they are in operation, and heat dissipation is a difficult problem faced by ultra-large-scale integrated circuits. Superconducting computer in the ultra-large-scale integrated circuits, the interconnecting lines between its components with near-zero resistance and ultra-micro heat superconducting devices to produce, there is no heat dissipation problems, while the computer's computing speed is greatly increased. In addition, scientists are studying the use of semiconductors and superconductors to make transistors, or even completely use superconductors to make transistors. Fusion reactor "magnetic closure" nuclear fusion reaction, the internal temperature of up to 100 million to 200 million degrees Celsius, there is no conventional material can accommodate these substances. The superconductor produces a strong magnetic field can be used as a "magnetic closure", the thermonuclear reactor in the ultra-high-temperature plasma surrounded, constrained, and then slowly released, so that controlled fusion energy as the 21st century promising new energy. Scientists have recently created a new form of matter and predict that it will help mankind make the next generation of superconductors that can be used for a variety of purposes, such as generating electricity and improving the efficiency of trains. This new form of matter, called a "Fermi condensate," is the sixth known form of matter. The first five forms of matter are gases, solids, liquids, plasmas and the Bose-Einstein condensate, which was just invented in 1995. The major difference between fermions and bosons is in the quantum mechanical property of "spin". Fermions are particles like electrons with half-integer spins (e.g. 1/2, 3/2, 5/2, etc.), while bosons are particles like protons with integer spins (e.g. 0, 1, 2, etc.). This difference in spin gives fermions and bosons completely different properties. No two fermions can have the same quantum state: they do not have the same properties and cannot be in the same place at the same time; whereas bosons are capable of having the same properties. Thus, when physicists cooled a certain number of rubidium and sodium atoms into bosons in 1995, most of the atoms turned into the same low-temperature quantum state, becoming in effect a single giant monolithic atom: a Bose I Einstein condensate. But fermions like potassium I 40 or lithium I 6 must have slightly different properties for each particle, even at very low temperatures.