Products

About

©2019 StudyMode.com

Superconductors

Topics: Superconductivity, Absolute zero, BCS theory Pages: 2 (542 words) Published: October 8, 1999
Super conductivity is a natural phenomenon in which certain materials such as metals, alloys, and ceramics, can conduct electricity without resistance. These materials are what we call superconductors. In a superconductor, once the flow of electrons begins, it essentially goes on forever, making it an important material to humans.

Superconductivity was discovered by a Dutch scientist by the name of Heike Kamerlingh Onnes in 1911. While researching properties of materials at absolute zero, this man found out that certain materials lost its resistance to the flow of electrons. For years to come, his discovery was at the head of theoretical interest. The only problem though, was that people at that time could not even think of a way to produce such a temperature, to allow materials to be superconductors at all times. This all changed in 1986 when Karl Muller and George Bednorz were working at the IBM Research Division in Zurich, Switzerland. They found a material that reached superconductivity at around 35 degrees Kelvin or –238 degrees Celsius. In the next year, a team of Chinese-American physicists declared that they had found a material that reached superconductivity at 92 degrees Kelvin. This was a big improvement. 92 degrees Kelvin is not a very high temperature, in fact, it is the equivalent of –181 degrees Celsius. Locating superconducting material above 77 degree Kelvin is a good thing because it means that the material will be easily produced and used. A theoretical understanding of superconductivity was advanced in 1957 by American physicists John Bardeen, Leon Cooper, and John Schrieffer. Their Theories of Superconductivity became know as the BCS theory (which came from each mans last name) and won them a Nobel prize in 1972. The BCS theory explained superconductivity at temperatures close to absolute zero. However, at higher temperatures and with different superconductor systems, the BCS theory has consequently became insufficient to fully...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Superconductors Essay

    ...K YADAV (B.TECH 1ST yr) Superconductivity "The discovery of superconductors" The phenomenon of superconductivity, in which the electrical resistance of certain materials completely vanishes at low temperatures, is one of the most interesting and sophisticated in condensed matter physics. It was first discovered by the Dutch physicist Heike Kamerlingh Onnes, who was the first to liquefy helium (which boils at 4.2 Kelvin at standard pressure). In 1911 Kamerlingh Onnes and one of his assistants discovered the phenomenon of superconductivity while studying the resistance of metals at low temperatures. They studied mercury because very pure samples could easily be prepared by distillation. The historic measurement of superconductivity in mercury is shown in Figure 1. As in many other metals, the electrical resistance of mercury decreased steadily upon cooling, but dropped suddenly at 4.2 K, and became undetectably small. Soon after this discovery, many other elemental metals were found to exhibit zero resistance when their temperatures were lowered below a certain characteristic temperature of the material, called the critical temperature, Tc, some of which are given in Figure 2. Figure 1. The resistance of mercury measured by Onnes. Figure 2. The critical temperatures of some superconductors. In 1933, Walter Meissner and Robert Ochsenfeld discovered a magnetic phenomenon that showed that superconductors are not just...

    Read More
    3606 Words 11 Pages
  • Superconductors Research Paper

    ...and atomic spectral lines[->5], superconductivity is a quantum mechanical[->6]phenomenon. It is also characterized by a phenomenon called the Meissner effect[->7], the ejection of any sufficiently weak magnetic field from the interior of the superconductor as it transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of perfect conductivity[->8] in classical physics[->9]. The electrical resistivity[->10] of a metallic conductor[->11] decreases gradually as the temperature is lowered. However, in ordinary conductors[->12] such as copper[->13] and silver[->14], this decrease is limited by impurities and other defects. Even near absolute zero[->15], a real sample of copper shows some resistance. Despite these imperfections, in a superconductor the resistance drops abruptly to zero when the material is cooled below its critical temperature. An electric current[->16] flowing in a loop ofsuperconducting wire[->17] can persist indefinitely with no power source. In 1986, it was discovered that some cuprate[->18]-perovskite[->19] ceramic[->20] materials have critical temperatures above 90 K (−183 °C). These high-temperature superconductors[->21] renewed interest in the topic because of the prospects for improvement and potential room-temperature superconductivity. From a practical perspective, even 90 kelvins is relatively easy to...

    Read More
    6241 Words 20 Pages
  • Physics- Superconductors Essay

    ...A superconductor is a metallic alloy that conducts electricity without resistance, below a certain temperature. Once in motion, an electrical current will flow in a closed loop within a superconducting material. This is the closest to scientists of a perpetual motion machine. In 1911, Heike Kamerlingh Onnes first observed superconductivity. He used mercury and cooled to four degrees Kelvin. When the mercury reached that temperature, the resistance disappeared. That meant that the electrical current flowed freely through it. In 1933, the “Meissner effect” was discovered. It told of a magnet moving by a conductor by electrical currents in a conductor. This effect is the basis for conventional generators. However, superconductors the magnet is repulsed. The current is mirrored through the field that would have been penetrated. This is called magnetism and causes magnet to be levitated above superconductor material. In 1989, the Illinois Superconductor was the first to commercialize “high temperature” superconductors. They introduced medical equipment that operated at the temperature of seventy seven degrees Kelvin. Additionally, in Japan in 1997, introduced Yamanashi MAGLEV Test Line. In 2003 the train ran at a speed of 361 mph. There are other trains like the Japanese one like in England, Shanghai, and US. Biomagnetism is another use for superconductors. Current MRI’s use...

    Read More
    329 Words 2 Pages
  • Elements on Superconductors Essay

    ...Every material that is used by scientists has three important properties. The type of atoms that material is made of is important. Materials are split up into two types, neutral elements and compound elements. Neutral elements have the exact same number of protons and electrons, thus canceling each other out and making the material neutral. The way that the atoms are arranged is also important. This determines how the element will interact with others. Lastly the way that the atoms are bonded to each other is essential. This determines the structure and strength of the material. Silicon based semiconductors have become a major part of our society. Of all of the inventions in the last century the silicon semiconductor is arguably one of the most influential. This component has allowed technology to enhance and expand at an astonishing rate. You will find semiconductors at the core of every microchip as well as almost all transistors. Any object that is computerized depends on these semiconductors. Silicon is the basis of these semiconductors and a key component in all modern electronics. The use of silicon has allowed for the creation of microelectronics, which has completely revolutionized the computing industry within the past three decades. The use of silicon based semi conductors have led to the Information Age The biggest advantage of using silicon in electronics is that many silicon based devices can be built on a micron scale and placed on a single micro chip,...

    Read More
    873 Words 3 Pages
  • American Superconductor Essay

    ...at issue Recommend options that would be consistent with the organization’s accounting practices, accounting processes, and accounting-related departments. Include the last two years of published accounting statements. American Superconductor is a company which develops technologies and solutions for electric power. The organization decided to utilize an equity financing accounting principle in their businesses decisions which was fairly controversial as many believe that is not a wise way for a business to operate. Skeptics of debt financing believe that the risks are too high. For example, the company would still be obligated to pay back loans regardless of whether the business survives. In addition, they may face high interest rates and they may be required to provide cash or collateral before utilizing equity. Also, the decision may destroy the company's credit rating as they will constantly be displayed as in debt. In addition, when utilizing money from investors, startup companies are unlikely to benefit from equity financing because investors are not likely to invest in this type of un-established business. Therefore, this not an ideal option for new businesses. These are some of the disadvantages in which American Superconductor may face in this decision. However, American Superconductor's risky decision has several benefits for choosing to adopt equity financing strategies. One of these benefits includes tax deductions....

    Read More
    731 Words 3 Pages
  • Superconductor Technologies Essay

    ...1. Financial Analysis In order to evaluate the incentive system, the analysis of the current situation of STI needs to be put into the first place because there is no fit-for-all incentive system and the one fits the company best can be seen as a optimistic choice. Based on the brief financial report shown in the case, there are two major facts which seems will be effecting the incentive plan. 1.This company is on its rising stage, whose net sales boosts over 30% averagely each year and shows a high accelerate rate in recent years. As a lot of high-tech companies, its high ROA and ROE had proofed its strong profitability. 2. It suffers a high cost and especially high selling, general & admin expenses, which leads a low gross income and a negative net income. Regardless of the high cost of goods which may caused by the high scrap rate inevitable in this pioneer industry, the SG$A expenses which take over 84.3% of the net sales seems rather a burden to STI. NVIDIA, a leading high-tech producer, spend only 7.9% on SG&A comparing to its total return in 2002. Although there seems no more clues to screen the exact admin expense in the case, simply multiplying the figure of the average compensation paid to the top managers by 30, the figure seems to be over 6 million excluding the securities options, nearly 30% of the net sales and 200% the gross income. 2. Policy Analysis Now we have a big picture of the company, which is someone on its boost stage to the bright future...

    Read More
    736 Words 2 Pages

Popular Essays

Become a StudyMode Member

Sign Up - It's Free