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Russian physicists a superconducting DIAMONDS
Physics of the Russian Academy of Sciences created a new modification of the diamond having superconducting properties, according to the journal Nature. Vladimir Sidorov and his colleagues from the Institute of High Pressure Physics and Physics Institute, with the participation of the United States National Laboratory staff at Los Alamos managed to get an artificial diamond from carbon with the addition of boron at high temperatures and pressures.
These diamonds were obtained before, but this time the new material proved superconducting at a temperature of about 4 K. The superconducting properties were maintained and under the influence of strong magnetic fields. Under normal conditions, the diamond is an insulator, has a good thermal conductivity, and does not change its properties in high electric fields. These features make diamond attractive for use in different fields of electronics. boron additive greatly affect the electrical properties of diamond, which thus becomes a semiconductor. Boron by itself, one of the light elements in nature, it becomes a superconductor by cooling to 6 K and under pressure up to 160 GPa.
The group of Russian scientists managed to introduce boron into the diamond lattice. The material was obtained by reaction of boron carbide (B4C) with graphite at a temperature of about 2500 K and a pressure of 8 GPa. Reaction lasted for several seconds, the resulting boron concentration in the diamond were 2.3%. Russian physicists have measured the electrical resistance and magnetic susceptibility and found that the transition temperature to the superconducting state 4 K, a critical magnetic field, in which there remains superconducting state is 3.5 Tesla.
Vladimir Sidorov and his colleagues believe that the behavior of the new material could well be explained by the BCS theory (Bardeen-Cooper-Schrieffer), which introduces the interaction of electrons and phonons (lattice vibrations), whereby electrons can overcome the mutual electrostatic repulsion and grouped in pairs . It is worth noting that the work of Russian scientists and their American colleagues will be subjects of criticism from the scientific community - evidence of superconductivity is only indirect. Physicists are going to continue and expand research, examining the possibility of introducing supplements elements of the fourth group (germanium and silicon) in the diamond lattice structure.
print version
PS material is protected.
Publication date 23.05.2004gg.
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