What and how to measure - Quantities & Units

Quantity Symbol SI (Système International d’Unités) CGS (centimeter-gram-second system) Conversion Factor  
Anisotropy energy K J m-3 erg cm-3 10-1 View
Bohr magneton μΒ 0.927 x 10-23 J/T ( = Am-2) 0.927 x 10-20 erg/Oe ( = emu) View
Coercivity Hc KA m-1 1 Oe View
Curie Temperature Tc 0C View
Demagnetization factor Nd 0<N<1 0<N<4 1/4π View
Density d kg m-3 View
Energy product (BH) J m-3 erg/cm3 10-1 View
Exchange stiffness A J m-1 10-6 erg/cm View
Gyromagnetic ratio γ mA−1 s−1 s−1 Oe−1 4πx10−3 View
Hall coefficient RH m3 C−1 View
Heat capacity c J K−1 View
Hysteresis Loss/Cycle Pb J m−3 View
Inductance L H View
Magnetic 'charge' qm Am View
Magnetic constant μ0 H m−1 GOe−1 4π×10−7 View
Magnetic dipole moment j Wb·m emu, erg/G 4π × 10-10 View
Magnetic field strength H A m−1 1Oe 1 A m−1= 4π x 10−3Oe View
Magnetic flux Φ Wb or 10−8T m2 1G cm2 or Mx (Maxwell) 10−8 View
Magnetic flux density B T 1G (Gauss) 10−4 View
Magnetic flux quantum Φ0 Wb View
Magnetic induction B 10−4 T 1G (Gilbert) 1 Wb/m2 = 104 Gauss View
Magnetic moment m A m2 1 erg G−1 or emu 10−3 View
Magnetic polarization J T emu/cm3 4π × 10-4 View
Magnetic potential difference U A 1Gb 10/4π View
Magnetization (Volume) M A m−1 1 Oe or emu cm−3 1A m-1 = 10-3 Maxwell/cm2 View
Magnetization (Mass) σ, M A·m2 kg-1 emu/g 1 View
Magnetomotive force F A View
Mass susceptibility χg m3 kg−1 ergG-1 g-1 Oe-1 4π×10-3 View
Molar susceptibility χmol m3mol−1 emu mol−1Oe−1 4π×10−6 m3mol−1 View
Nuclear magneton μΝ 10−27 J T−1 10−24 erg G−1 View
Permeability (B/H) μ H m−1 GOe−1 4π × 10−7 H m−1 = 1emu View
Permeance Pm T m2 A−1 View
Reluctance Rm A T−1 m−2 View
Remanence Br T 1G View
Resistivity ρ Ω m View
Scalar potential ϕ A View
Specific domain wall energy γ J m−2 erg cm−2 10−3 View
Specific moment σ A m2 kg−1 View
Susceptibility (volume) χ 4? × 1 χm = 4π χ'm View
Vector potential A T m View
General informations for magnetism units
1.  1G = 10−4 T
2.  1Oe = 103 / 4π  Am−1 ≈ 80 Am−1
3.  1 emu g−1 = 1 J T−1kg−1 and  1 emu =1 mA m2
4. The unit of magnetic field strength H has no special name; H is measured in amperes per meter (A m−1).
The magnetic induction or magnetic flux density B (or simply B-field) has the tesla (T) as the unit and is related to the magnetic field intensity H through the magnetic constant or vacuum magnetic permeability μ0, that has a value of 4π × 10−7 H m−1 in the SI.
5. The relations between B and H in the two systems of units are:
B = μ0(H+M) (SI)
B = H+4πM (CGS)
In the last equation (in the centimeter-gram-second system (CGS)) B is measured in gauss (G) and the unit of H is the oersted (Oe). In the CGS system the constant 4π appears explicitly in the expression of B.