Superconductivity

superconductor - сверхпроводник;

a scale - шкала;

diamagnetism - диамагнетизм;

levitate - подниматься;

tunneling phenomenon - туннельный эффект;

trigger - запускать, давать начало;

indeterminate - неопределенный,

Superconductors, materials that have no resistance to the flow of electricity, are one of the last great frontiers of scientific discovery. Not only have the limits of superconductivity not yet been reached, but the theories that explain superconductor behavior seem to be constantly under review. In 1911 superconductivity was first observed in mercury by Dutch physicist Heike Kamerlingh Onnes of Leiden University. When he cooled it to the temperature of liquid helium, 4 degrees Kelvin (–269°C), its resistance suddenly disappeared. The Kelvin scale represents an “absolute” scale of temperature. Thus, it was necessary for Onnes to come within 4 degrees of the coldest temperature that is theoretically attainable to witness the phenomenon of superconductivity. Later, in 1913, he won a Nobel Prize in physics for his research in this area.

The next great milestone in understanding how matter behaves at extreme cold temperatures occurred in 1933. German researchers Walter Meissner and Robert Ochsenfeld discovered that a superconducting material will repell a magnetic field. A magnet moving by a conductor induces currents in the conductor. This is the principle upon which the electric generator operates. But in a superconductor the induced currents exactly mirror the field that would have otherwise penetrated the superconducting material – causing the magnet to be repulsed. This phenomenon is known as strong diamagnetism and is today often referred to as the “Meissner effect”. The Meissner effect is so strong that a magnet can actually be levitated over a superconducting material.

In subsequent decades other superconducting metals and compounds were discovered. But the first widely-accepted theoretical understanding of superconductivity was advanced in 1957 by American physicists John Bardeen, Leon Cooper, and John Schrieffer. Their Theory of Superconductivity became known as BCS theory, derived from the first letters of each man’s last name – and won them a Nobel Prize in 1972.

Another significant theoretical advancement came in 1962 when Brian D. Josephson, a graduate student at Cambridge University, predicted that electrical current would flow between two superconducting materials – even when they are separated by a non-superconductor or insulator. His prediction was later confirmed and won him a share of the 1973 Nobel Prize in physics. This tunneling phenomenon is known today as the “Josephson effect” and has been applied to electric devices such as SQUID (superconducting quantum interference device), an instrument capable of detecting the weakest magnetic field.

A truly breakthrough discovery was made in the field of superconductivity in1986. Alex Miller and Georg Bednorz, researchers at the IBM Research Laboratory in Ruschlicon (Switzerland), created a brittle ceramic compound that superconducted at the highest temperature then known: 30K. What made this discovery so remarkable was that ceramics are normally insulators. The Lanthanum, Barium, Copper and Oxygen compound that the scientists synthesized, behaved in a not-yet-understood way. The discovery of this first of the superconducting copper-oxides (cuprates) won the two men a Noble Prize the following year. It was later found that tiny amounts of this material were actually superconducting at 58 K, due to a small amount of lead having been added as a calibration standard – making the discovery even more noteworthy.

Muller and Bednorz’s discovery triggered a flurry of activity in the field of superconductivity. Researchers around the world began “cooking” up ceramics of every imaginable combination in a quest for higher and higher Tc’s.

Note: SQUID – сверхпроводящий квантовый интерференционный датчик, СКВИД

Task 9 Find equivalents to the following phrases In the text:

1) передний край научных открытий;

2) постоянно пересматривать;

3) теоретически достижимый;

4) следующая значительная веха;

5) отталкивать магнитное поле;

6) значительное теоретическое продвижение;

7) его предсказание было позднее подтверждено;

8) хрупкое керамическое соединение;

9) вести себя непонятным образом;

10) из-за небольшого количества добавленного свинца;

11) вызвать рост активности

Task 10 Form word combinations by matching the words from 1-11 with the words a-l and translate them:

1. induced 2. breakthrough 3, weakest 4. subsequent 5. superconducting

6. widely-accepted 7. electric 8. ceramic 9. strong 10. tiny 11. theoretical

a) amount b) decades c) current d) materials e) generator

f) understanding g) diamagnetism h) magnetic field i) compound

j) discovery k) advancement

Task 11

Writing

Read the text and give a summary in English (in written form)

Пётр Леонидович Капица (1894–1984), русский физик; удостоен в 1978 Нобелевской премии за фундаментальные открытия и изобретения в области физики низких температур. Родился 26 июня (8 июля) 1894 в Кронштадте. Окончил Петроградский политехнический институт (1918). Руководителем дипломной работы Капицы был академик А.Ф.Иоффе. На его же кафедре Капица остался работать после окончания института.

Работал в Кембриджском университете в лаборатории у Э.Резерфорда. Там он выполнил исследования по a- и b-излучению, создал метод получения сильных магнитных полей. За эти работы он в 1923 получил премию им. Дж. Максвелла. В 1929 был избран членом Лондонского королевского общества и членом-корреспондентом АН СССР. Наибольшую известность Капице принесли его новаторские экспериментальные исследования в области физики низких температур, создание техники для получения импульсных сверхсильных магнитных полей, работы по физике плазмы. В 1938 открыл необычное свойство жидкого гелия – резкое уменьшение вязкости (viscosity) при температуре ниже критической (2,19 К), получившее название сверхтекучести. Эти исследования стимулировали (encourage) развитие квантовой теории жидкого гелия, разработанной Л.Ландау.

Task 12

Speaking

Give a talk on one of the famous physicists who made great discoveries in the field of electricity, speak about his life and achievements.

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