Soviets Sprinting To Apply Superconductivty Concepts

Throughout its entire history, physics seems to have never before experienced a boom similar to that brought on by the higher temperature discovery of Bednon and Müller in 1986. Thousands of researchers throughout the world are now striving to outreach one another, conducting hundreds of experiments, solving innumerable equations, and publishing thousands of papers. Alongside academies and universities, government agencies are also discussing superconductivity problems. What has happened only recently is something that physicists have been seeking for 80 years and what most of them, to tell the truth, had ceased to hope for. By discovering substances that become superconductors at much higher temperatures than previously, exceeding that of liquid nitrogen (77.4 K), the pathway has been opened up for industrial applications using these new superconducting materials. In the Soviet Union, the investigation of high-temperature superconductivity has become the number one priority for a great many laboratories. Preliminary experiments have already demonstrated that we will need to solve an intricate complex of physico-chemical problems before being able to obtain high-temperature superconductors with “convenient” properties. Classical superconductors admit to being bent, soldered, and forged—and this is highly important for any applications. However, these modifications are not always possible with oxides. The new superconductors are relatively nonworkable and are, moreover, unstable. Even contact with water may significantly alter the properties of the main high-temperature superconductor known as “1-2-3,” (as, for example, in Y1Ba2CuO7). Therefore, we must look for new substances and compositions, so that we may have more choices in designing objects for practical use. Such work is being actively pursued at the Soviet Academy of Sciences and at many universities in the Soviet Union. Large-scale research into the synthesis of new substances is being headed by Y. Tretyakov and A. Merzhanov. Investigation into their atomic crystalline structure is being supervised by V. Vainshtein and V. Simonov. Today in the Soviet Union, as in other countries, substances containing bismuth or thallium have become particularly “fashionable.” The second chief priority shared by researchers is the study of the fundamental properties of these high-temperature superconductors. We do not yet precisely understand what makes these materials superconducting and what signs to seek in searching for their analogs. Therefore, it is now the 'experimenters’ turn. On the basis of investigations made in Soviet laboratories, it has been found that the famous “1-2-3” substance is bulk metal and that it has no unidirectional semiconductor properties, as it appeared to have at first. We can now state firmly that superconducting current is flowing throughout the cross-section of this sub- stance rather than only along grain boundaries as was formerly assumed. By means of experiments in combination light scattering, it has been possible to observe how different atoms oscillate in this substance. All this is highly important for constructing a physical model of high-temperature superconductivity. This explains why these and other problems were discussed in such detail and with such intensity by participants at the latest world conference on superconductivity in Interlaken, Switzerland. As was made plain by that meeting, many of the experimental data obtained recently have contradicted established theoretical concepts. In particular, the results of experiments on metallic electroconductivity of single crystals, reported by I. Shchegolev, Institute of Solid-Sate Physics, Soviet Academy of Sciences, failed to agree with the infer- ences deduced from the theory of Nobel laureate Philip Anderson of Princeton. Shchegolev’s data were supported by two Japanese scientists, S. Tanaka and K. Kitazawa of the Tokyo University. Thus, international cooperation and competition between scientists from different countries is contributing to progress in our understanding the nature of high-temperature superconductivity. The third important issue is the physics of superconducting films. All potential applications in microelectronics, in the use of Josephsonian effects and microbridges, are in one manner or another associated with films. While films are manufactured by processes quite different from those used to create bulk substances of the same composition, Soviet scientists have been able to develop poly- and monocrystalline films of the “1-2-3” type—synthesized films capable of withstanding even greater densities of superconducting current. Are Soviet physicists satisfied with their achievements in high-temperature superconductivity? Generally, yes. They are today working at a world-class level, and yet, at the same time, not quite. The point is that many Soviet laboratories lack adequate equipment. To a certain degree, this has proven to be helpful because it compelled Soviet scientists to do more thinking, to be more creative. But at present, when time is of the essence, it is recognized that there is a real need for the most up-to-date and efficient instruments. And in this respect, unfortunately, the Soviet instrument-making industry lags behind those of the Japanese and Americans. Thus, Soviet physics today must solve not only scientific but also organizational problems: We are simultaneously staging experiments in physics and in physics- oriented sociology. Concurrently, the large-scale restructuring program now underway in the Soviet Union is stepping up the rate of scientific research. Academician Yuri Andreyevich Osipyan is director of the Institute of Solid State Physics of the Soviet Academy of Sciences, Moscow. Osipyan was awarded a Lenin Prize for Science and Technology in 1978.

Soviets Sprinting To Apply Superconductivty Concepts

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