| Dielectric Behavior | Magnetic Behavior | ||
| Charge q | No equivalent | ||
| Electrical field E | Magnetic field H | ||
| Electrical displacement D | (Magnetic) Induction B | ||
| Permittivity constant of vacuum e0 | Permeability constant of vacuum m0 | ||
| Relative dielectric constant of material er |
Relative permeability constant of material mr | ||
| From Maxwell equations | From Maxwell equations | ||
| Connection between dielectric flux density D, electrical field E, and relative dielectric constant er | D = e0 · er · E | B = m0 · mr · H | Connection between magnetic flux density B, magnetic field H, and relative (magnetic) permeability mr |
| Formulation with electrical Polarization P in the material caused by the electrical field | D = e0 · E + P | B = m0 · H + J | Formulation with magnetic polarization J in the material caused by the magnetic field |
| Justified by theory of polarization mechanisms | Justified by theory of magnetization mechanisms | ||
| Material "law" describing P as response of a material to a field E and defining
the dielectric susceptibility c Note exception: Ferroelectricity |
P = e0 ·c · E | J = m0 · cmag · H | Material "law" describing J as response of a material to a field H and defining
the magnetic susceptibility
cmag Note exception: Ferromagnetism |
| Relation between c and er | c = er – 1 | cmag = mr – 1 | Relation between cmag and mr |
| Definition of P as material property in terms of electrical dipole moment m and density NV | P = <m> · NV | J = <m> · NV | Definition of J as material property in terms of magnetic moments m and density NV |
| M = J/m0 | Definition of magnetization M | ||
| M = cmag · H | Relations between M and H | ||
| Dielectric Polarization | Magnetic Polarization | ||
| Electronic polarization | Diamagnetism | ||
| Induce dipole moments by displacing electrons and nuclei. Weak for spherical atoms. Stronger for covalent bonds. Important for optics. | er » 1,0001 .... 30 | mr » 0,9999 | Induce precession of electrons. Always very weak and opposite to field. Not important. |
| Orientation polarization | Paramagnetism | ||
| Average small orientation of fluctuating existing dipoles. Only in liquids; can be large. Not important. | er » 2 ..... 100 | mr » 1,0001 | Average small orientation of existing dipoles free to rotate in solids. Always small; not important. Extreme case: Ferromagnetism. |
| Ionic polarization | No direct counterpart | ||
| Net dipole moment from distribution of charges. Important. |
er » 2 ... 100 | ||
| Ferroelectricity Natural dipoles defined by crystallography are lined up. Important. | er > 1000 | mr > 1000 | Ferromagnetism Natural magnetic moments are lined up in any directions (with crystal directions preferred). Extremely important. |
With frame
4.1.1 Magnetic Materials