Bismuth electrical resistivity

It is a white crystalline, brittle metal with a pinkish tinge. It occurs native. Bismuth is the most diamagnetic of all metals, and the thermal conductivity is lower than any metal, except mercury. It has a high electrical resistance, and has the highest Hall effect of any metal (i.e., greatest increase in electrical resistance when placed in a magnetic field). 

Calvet and Guillaud (S3) noted in 1965 that in order to increase the sensitivity of a heat-flow microcalorimeter, thermoelectric elements with a high factor of merit must be used. (The factor of merit / is defined by the relation / = e2/pc, where e is the thermoelectric power of the element, p its electrical resistivity, and c its thermal conductivity.) They remarked that the factor of merit of thermoelements constructed with semiconductors (doped bismuth tellurides usually) is approximately 19 times greater than the factor of merit of chromel-to-constantan thermocouples. They described a Calvet-type microcalorimeter in which 195 semiconducting thermoelements were used instead of the usual thermoelectric pile. 

Potassium and sodium are good conductors of heat.23 If the conductivity of silver be unity, that of sodium is 0 365. J. W. Hornbeck found the temp, coeff. of the thermal conductivity of potassium or sodium falls with rise of temp. The alkali metals are also good conductors of electricity 24 for example, the conductivity of sodium for heat and electricity is exceeded only by silver, copper, and gold. According to E. F. Northrup, the metals sodium, potassium, mercury, tin, lead, and bismuth have the same value for the ratio of the coeff. of electrical resistance to the coeff. of cubical expansion at the same temp. The electrical conductivity of lithium is nearly ll-4xl04 reciprocal ohms at 20°, that is, about 20 4 per cent, of the conductivity of hard silver of sodium at 2T 70, 22 4 XlO4 reciprocal ohms, that is, about 36 5 per cent, of the value of silver. 

The electrical conductivity of a pure arsenic crystal has been measured 3 at temperatures down to 2-42° Abs. The resistance-temperature curve is similar to those of pure metals. There is evidence of definite residual resistance being maintained at low temperatures, but arsenic does not exhibit the abnormally high residual resistance shown by bismuth, nor does it show superconductivity. The resistance is by no means proportional to the absolute temperature. It has been estimated that the electrical resistance of liquid arsenic at the melting point is about 0-4 of that of the solid phase.4... 

An interesting series of bismuth cuprates in terms of the variation of the Tc as well as the hole concentration with composition is provided by Bi2Sr2Ca1 a.Lna.Cu208 where Ln = Y or rare earth (Rao et al. 19906). The electrical resistivity data show a metal-insulator transition in the normal state with change in x (figure 12). The Ta as well as the nb show a maximum at a composition of x = 0.25 (figure 13). Note that when Ca is fully substituted by Ln, the material becomes a non-superconducting insulator. Hole concentration in these bismuth cuprates is readily determined by Fen-Fem redox titrations. 

Mercury has a high density (13.546 g cm" at 20 °C) and a wide liquid range (mp -38.9 °C bp 357) over most of which its volume expands uniformly. In addition, the high surface tension of mercury keeps it from sticking to glass surfaces. These properties have contributed to its use in an impressive number of laboratory applications. For a metal, mercury has an unusually high electrical resistivity or specific resistance (95.8 J,S2 cm), and this property enables it to be used as an electrical standard. Of all the common metals, only bismuth has a higher resistivity. 

Magnetic quantum oscillations in bismuth were first observed in the field dependence of the electrical resistivity by Shubnikov and de Haas [246] shortly before the dHvA effect was discovered. Usually, however, the SdH effect is weak and hard to observe except in semimetals, like bismuth, and semiconductors. 

Arsenic, antimony, and bismuth also exhibit a variety of allotropes. The most stable allotrope of arsenic is the gray (a) form, which is similar to the rhombohedral form of phosphorus. In the vapor phase, arsenic, like phosphorus, exists as tetrahedral AS4. Antimony and bismuth also have similar a forms. These three elements have a somewhat metallic appearance but are brittle and are only moderately good conductors. Arsenic, for example, is the best conductor in this group but has an electrical resistivity nearly 20 times as great as copper. 

The electrical resistance of solid bismuth is greater than that of liquid bismuth, the ratio of liquid to solid resistivity being approximately 0.5-0.8 for most metals this ratio is 2.0. The linear dependence of resistivity on temperature does not hold for temperatures below 10 K. High thermoelectric effects are produced when bismuth is coupled with certain other metals. Of all metals, it is the most diamagnetic and the increase in resistivity in a magnetic... 

Bismuth is a metal, white with a pinkish tinge. It is a poor conductor of heat and electricity. Its electrical resistance is increased in a magnetic field to a larger extent than any other metal. Bismuth is also the most diamagnetic of all metals. 

Solders. In spite of the wide use and development of solders for millennia, as of the mid-1990s most principal solders are lead- or tin-based alloys to which a small amount of silver, zinc, antimony, bismuth, and indium or a combination thereof are added. The principal criterion for choosing a certain solder is its melting characteristics, ie, soHdus and Hquidus temperatures and the temperature spread or pasty range between them. Other criteria are mechanical properties such as strength and creep resistance, physical properties such as electrical and thermal conductivity, and corrosion resistance. 

Bismuth is more resistant to electrical current in its solid state than it is in its liquid form. Its thermal conductivity is the lowest of all metals, except mercury. Even though it is considered a metal-like element, it is a very poor conductor of heat and electricity. 

One fateful day in 1980, as the people down at the Institute of Electrical and Electronic Engineers like to tell the story, Rustum Roy, a physical chemist at Penn State, became disenchanted with his experiments in superconductivity, which is the ability of some substances, when cooled to very low temperatures, to conduct electricity without resistance and without loss. He had been experimenting for five years with ceramics—notably with a barium-lead-bismuth oxide mixture—but despite the long hours and the hard work, he could not get his concoction to superconduct at temperatures any higher than a few degrees above what one might encounter in outer space. 

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