high-temperature superconductors

(noun)

Materials that behave as superconductors at unusually high temperatures (above about 30 K).

Related Terms

Examples of high-temperature superconductors in the following topics:

  • Primary Market Research

    • An example of primary research in the physical sciences: Can the transition temperature of high-temperature superconductors be increased by varying the composition of the superconducting material.
    • The scientist will modify the composition of the high-Tc material in various ways and measure the transition temperature of the new material as a function of its composition.
    • An example of primary research in the physical sciences: Can the transition temperature of high-temperature superconductors be increased by varying the composition of the superconducting material.
    • The scientist will modify the composition of the high-Tc material in various ways and measure the transition temperature of the new material as a function of its composition.

  • Temperature and Superconductivity

    • When a superconductor is placed in a weak external magnetic field H, and cooled below its transition temperature, the magnetic field is ejected.
    • Usually, conventional superconductors have critical temperatures ranging from around 20 K to less than 1 K.
    • High-temperature superconductors can have much higher critical temperatures.
    • For example, YBa2Cu3O7, one of the first cuprate superconductors to be discovered, has a critical temperature of 92 K; mercury-based cuprates have been found with critical temperatures in excess of 130 K.
    • Describe behaviors of a superconductor below a critical temperature and in a weak external magnetic field

  • X-Ray Spectra: Origins, Diffraction by Crystals, and Importance

    • For example, current research in high-temperature superconductors involves complex materials whose lattice arrangements are crucial to obtaining a superconducting material.

  • Dependence of Resistance on Temperature

    • Resistivity and resistance depend on temperature with the dependence being linear for small temperature changes and nonlinear for large.
    • Some materials can become superconductors (zero resistivity) at very low temperatures (see ).
    • The temperature coefficient is typically +3×10−3 K−1 to +6×10−3 K−1 for metals near room temperature.
    • The resistance of a sample of mercury is zero at very low temperatures—it is a superconductor up to about 4.2 K.
    • Compare temperature dependence of resistivity and resistance for large and small temperature changes

  • Molecular Crystals

    • Thus, many corresponding substances are either liquid (water) or gaseous (oxygen) at room temperature.
    • Heating white phosphorus under high (GPa) pressures converts it to black phosphorus, which has a layered, graphite-like structure.
    • When white phosphorus is converted to the covalent red phosphorus, the density increases to 2.2–2.4 g/cm3 and melting point to 590 °C; when white phosphorus is transformed into the (also covalent) black phosphorus, the density becomes 2.69–3.8 g/cm3 with a melting temperature ~200 °C.
    • The structural transitions in phosphorus are reversible: upon releasing high pressure, black phosphorus gradually converts into the red allotrope, and by vaporizing red phosphorus at 490 °C in an inert atmosphere and condensing the vapor, covalent red phosphorus can be transformed back into the white molecular solid.
    • Fullerene solid is an insulator, but it can become a superconductor when intercalating metal ions are inserted between the fullerene molecules (C60).

  • Absolute Temperature

    • Absolute temperature is the most commoly used thermodyanmic temperature unit and is the standard unit of temperature.
    • Thermodynamic temperature is the absolute measure of temperature.
    • By using the absolute temperature scale (Kelvin system), which is the most commonly used thermodynamic temperature, we have shown that the average translational kinetic energy (KE) of a particle in a gas has a simple relationship to the temperature:
    • The kelvin (or "absolute temperature") is the standard thermodyanmic temperature unit.
    • Real gases do not always behave according to the ideal model under certain conditions, such as high pressure.

  • Water’s High Heat Capacity

    • Water is able to absorb a high amount of heat before increasing in temperature, allowing humans to maintain body temperature.
    • The high heat capacity of water has many uses.
    • The water then remains hot for a long time due to its high heat capacity.
    • Water's high heat capacity is a property caused by hydrogen bonding among water molecules.
    • Furthermore, because many organisms are mainly composed of water, the property of high heat capacity allows highly regulated internal body temperatures.

  • Gas Solubility and Temperature

    • Solubility of a gas in water tends to decrease with increasing temperature, and solubility of a gas in an organic solvent tends to increase with increasing temperature.
    • Several factors affect the solubility of gases: one of these factors is temperature.
    • When the temperature of a river, lake, or stream is raised abnormally high, usually due to the discharge of hot water from some industrial process, the solubility of oxygen in the water is decreased.
    • In severe cases, temperature changes can result in large-scale fish kills.
    • The trend that gas solubility decreases with increasing temperature does not hold in all cases.

  • Hyperthermophilic Archaea, H2, and Microbial Evolution

    • Many hyperthermophiles are also able to withstand other environmental extremes like high acidity or radiation levels.
    • There are a number of proposed high temperature adaptions of hyperthermophiles.
    • The protein molecules in the hyperthermophiles exhibit hyperthermostability - that is, they can maintain structural stability (and therefore function) at high temperatures.
    • Such hyperthermostable proteins are often commercially important, as chemical reactions proceed faster at high temperatures.
    • The cell membrane of hyperthermophiles contains high levels of saturated fatty acids, which are usually arranged in a C40 monolayer to retain its shape at high temperatures.

  • Hyperthermophiles from Terrestrial Volcanic Habitats

    • A hyperthermophile thrives at relatively high temperatures and can be found in geothermally heated regions of the Earth.
    • As a prerequisite for their survival, thermophiles contain enzymes that can function at high temperatures.
    • Thermophiles are classified into obligate and facultative thermophiles; obligate thermophiles (also called extreme thermophiles) require such high temperatures for growth, whereas facultative thermophiles (also called moderate thermophiles) can thrive at high temperatures, but also at lower temperatures (below 50°C).
    • Some extreme thermophiles (hyperthermophiles) require a very high temperature (80°C to 105°C) for growth.
    • Their membranes and proteins are unusually stable at these extremely high temperatures.