Superconducting lead particles produced by chemical techniques
The superconductivity of extremely small lead particles has been studied as a function of size, surface condition, and connectivity using chemical techniques to produce particles of well-controlled size and shape suspended in insulating media. Approximately monodisperse suspensions of equiaxed, rod, and lath-shaped particles of lead halides and other lead compounds suspended in gelatin, polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, methyl cellulose, and hydroxyethyl cellulose have been produced. These particles have been reduced to pseudomorphs of lead in the liquid phase or the suspensions have been coated on substrates and dried before reduction. Reducing solutions containing aminoiminomethanesulfinic acid are effective with particles of lead halides, lead phosphate, lead sulfate, and lead tartrate. Suspensions of smaller discrete lead particles have also been produced by direct reduction of solutions of soluble lead salts containing suitable polymers, chelating, and stabilizing agents. Dispersions with mean particle dimensions between 3 nm and 5 ..mu..m, and a narrow size-frequency distribution, have been produced. The superconductivity of the particles has been characterized by measurements of the magnetization as a function of temperature and magnetic field. The larger particles have a transition temperature of 7.2 K, the same as bulk lead; however, for particles of characteristic dimensions less than 20 nm, the transition temperature is lower by approx.0.1 K.
- Research Organization:
- Department of Physics, University of Virginia, Charlottesville, Virginia 22901
- OSTI ID:
- 5079213
- Journal Information:
- J. Appl. Phys.; (United States), Vol. 53:9
- Country of Publication:
- United States
- Language:
- English
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
LEAD
SUPERCONDUCTIVITY
CHELATES
CHEMICAL REACTIONS
EXPERIMENTAL DATA
GELATIN
LEAD PHOSPHATES
LEAD SULFATES
MAGNETIZATION
ORGANIC COMPOUNDS
PARTICLES
SHAPE
SIZE
SOLUTIONS
SUBSTRATES
SURFACES
SUSPENSIONS
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
COLLOIDS
COMPLEXES
DATA
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
INFORMATION
LEAD COMPOUNDS
METALS
MIXTURES
NUMERICAL DATA
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PHYSICAL PROPERTIES
PROTEINS
SULFATES
SULFUR COMPOUNDS
THERMODYNAMIC PROPERTIES
360104* - Metals & Alloys- Physical Properties
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