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Paramagnetism is the tendency of the atomic magnetic dipoles, due to quantum-mechanical spin, in a material that is otherwise non-magnetic to align with an external magnetic field. This alignment of the atomic dipoles with the magnetic field tends to strengthen it, and is described by a relative magnetic permeability greater than unity (or, equivalently, a small positive magnetic susceptibility).In pure paramagnetism, the field acts on each atomic dipole independently and there are no interactions between individual atomic dipoles. Such paramagnetic behaviour can also be observed in ferromagnetic materials that are above their Curie temperature.
Paramagnetic materials attract and repel like normal magnets when subject to a magnetic field. Under relatively low magnetic field saturation when the majority of the atomic dipoles are not aligned with the field, paramagnetic materials exhibit magnetisation according to Curie's Law:
where
- M is the resulting magnetisation
- B is the magnetic flux density of the applied field, measured in Tesla
- T is absolute temperature, measured in kelvin
- C is a material-specific Curie constant
This law indicates that paramagnetic materials tend to become increasingly magnetic as the applied magnetic field is increased, but less magnetic as temperature is increased. Curie's law is incomplete because it fails to predict what will happen when most of the little magnets are aligned (after everything is aligned, increasing the external field will not increase the total magnetization) so Curie's Constant really should be expressed as a function of how much of the material is already aligned.
Paramagnetic materials in magnetic fields will act like magnets but when the field is removed, thermal motion will quickly disrupt the magnetic alignment. In general paramagnetic effects are small ( magnetic susceptibility of the order of 10-3 to 10-5).
Ferromagnetic materials above the Curie temperature become paramagnetic.
1 Paramagnetic Materials
- Aluminum
- BariumBarium is also the latin name for the city Bari in Italy. Barium is a toxic chemical element in the periodic table that has the symbol Ba and atomic number 56. A soft silvery metallic element, barium is an alkaline earth metal and melts at a very high tem
- CalciumSee also Calcium, New York, United States. potassium calcium scandium Mg Ca Sr Full table General Name, Symbol, Numbercalcium, Ca, 20 Series alkaline earth metal Group, Period, Block 2 (IIA), 4, s Density, Hardness 1550 kg/m3, 1. 75 Appearance silvery whi
- Liquid OxygenOxygen is the chemical element in the periodic table that has the symbol O and atomic number 8. The element is very common, found not only on Earth but throughout the universe. Molecular oxygen (O, often called free oxygen on Earth is thermodynamically un
- PlatinumPlatinum is also a certification by the RIAA and other world recording industries, see: RIAA certification Platinum is a chemical element in the periodic table that has the symbol Pt and atomic number 78. A heavy, malleable, ductile, precious, gray-white
- SodiumSodium is the chemical element in the periodic table that has the symbol Na Natrium in Latin) and atom number 11. Sodium is a soft, waxy, silvery reactive metal belonging to the alkali metals that is abundant in natural compounds (especially halite).
- StrontiumStrontium is a chemical element in the periodic table that has the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. This metal turns yellow when
- Uranium
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