Curie temperature

Examples of Curie temperature in the following topics:

• Ferromagnets and Electromagnets

  • Increased thermal motion at higher temperature can disrupt and randomize the orientation and the size of the domains.
  • There is a well-defined temperature for ferromagnetic materials called the Curie temperature, above which they cannot be magnetized.
  • The Curie temperature for iron is well above room temperature at 1043 K (770ºC).
  • Several elements and alloys have Curie temperatures much lower than room temperature, and are ferromagnetic only below those temperatures.

• Discovery of Radioactivity

  • In addition, radiation does not vary with temperature, pressure, or ionization state of the uranium atom.
  • In 1898, Marie Curie began her doctoral study of Becquerel's rays.
  • The Curies' radium salt glowed visibly from the radiation.
  • Shortly after Marie completed her PhD, both Curies and Becquerel shared the 1903 Nobel Prize in Physics for their work on radioactivity.
  • Awarded the 1911 Nobel Prize in Chemistry for her discovery of two new elements, Curie remains the only person to win Nobel Prizes in both physics and chemistry.

• Dependence of Resistance on Temperature

  • Resistivity and resistance depend on temperature with the dependence being linear for small temperature changes and nonlinear for large.
  • The resistivity of all materials depends on temperature.
  • The temperature coefficient is typically +3×10−3 K−1 to +6×10−3 K−1 for metals near room temperature.
  • Above that critical temperature, its resistance makes a sudden jump and then increases nearly linearly with temperature.
  • Compare temperature dependence of resistivity and resistance for large and small temperature changes

• 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.
  • Thermodynamic temperature is an "absolute" scale because it is the measure of the fundamental property underlying temperature: its null or zero point ("absolute zero") is the temperature at which the particle constituents of matter have minimal motion and cannot become any colder.
  • 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.

• Blackbody Temperatures

  • A blackbody is of course characterized by a single temperature, $T$.
  • There are three characteristic temperatures in common usage: brightness temperature, effective temperature and the colour temperature.
  • The brightness temperature is determined by equating the brightness or intensity of an astrophysical source to the intensity of a blackbody and solving for the temperature of the corresponding blackbody.
  • In what regime does the linear relationship between the brightness temperature and the intensity begin to fail?
  • Finally the effective temperature is the temperature of a blackbody that emits the same flux at its surface as the source, i.e.

• Rate of Radioactive Decay

  • Another unit of radioactivity is the curie, Ci, which was originally defined as the amount of radium emanation (radon-222) in equilibrium with one gram of pure radium, isotope Ra-226.
  • At present, it is equal, by definition, to the activity of any radionuclide decaying with a disintegration rate of 3.7 × 1010 Bq, so that 1 curie (Ci) = 3.7 × 1010 Bq.

• Blackbody Radiation

  • A blackbody is of course characterized by a single temperature, $T$.
  • There are three characteristic temperatures in common usage: brightness temperature, effective temperature and the colour temperature.
  • The brightness temperature has several nice properties.
  • The colour temperature is defined by looking at the peak of the emission from the source and using Wien's displacement law to define a corresponding temperature.
  • Finally the effective temperature is the temperature of a blackbody that emits the same flux at its surface as the source, i.e.

• Absolute Zero

  • Absolute zero is the coldest possible temperature; formally, it is the temperature at which entropy reaches its minimum value.
  • Absolute zerois the coldest possible temperature.
  • Formally, it is the temperature at which entropy reaches its minimum value.
  • Therefore, it is a natural choice as the null point for a temperature unit system.
  • A brief introduction to temperature and temperature scales for students studying thermal physics or thermodynamics.

• Thermodynamics

  • A blackbody is of course characterized by a single temperature, $T$.
  • There are three characteristic temperatures in common usage: brightness temperature, effective temperature and the colour temperature.
  • The brightness temperature is determined by equating the brightness or intensity of an astrophysical source to the intensity of a blackbody and solving for the temperature of the corresponding blackbody.
  • In what regime does the linear relationship between the brightness temperature and the intensity begin to fail?
  • Finally the effective temperature is the temperature of a blackbody that emits the same flux at its surface as the source, i.e.

• Solid Solubility and Temperature

  • Solubility often depends on temperature; the solubility of many substances increases with increasing temperature.
  • The solubility of a given solute in a given solvent typically depends on temperature.
  • Many salts show a large increase in solubility with temperature.
  • Some solutes exhibit solubility that is fairly independent of temperature.
  • A few, such as cerium(III) sulfate, become less soluble in water as temperature increases.