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Home , Erg, Gaussian units, Gauss (unit), Gilbert (unit), Henry (unit), Maxwell (unit)

UNITS FOR MAGNETIC PROPERTIES

Conversion Quantity Symbol Gaussian & cgs emu a factor, C b SI & rationalized mks C Magnetic density, B (0) d 10-4 (T), Wb/m2 magnetic induction

Magnetic flux (Mx), G·cm2 (Wb), (V·s)

Magnetic potential difference, U,F (Gb) 10/477 (A) ma~netomotive

Magnetic field strength, H (Oe),e Gb/cm A/m! ,magnetizing force

(Volume) g M emu/cm3 h A/m

(Volume) magnetization 477M G A/m

Magnetic polarization, 1,1 emu/cm3 477 X 10-4 T, Wb/m2i intensity of magnetization

1 A.m 2/kg () magnetization (F, M emu/g 477 X 10-7 Wb·m/kg

3 2 m emu, /G 10- A.m , per tesla (l/T)

Magnetic moment j emu, erg/G 477 X 10- 10 Wb·m'

dimensionless (V01ume) susceptibility dimensionless, emu/cm3 per meter (H/m), Wb/(A.m)

X 3 3 3 477 10- m /kg (Mass) susceptibility K cm /g, emu/g Xp, p (477)2 X 10-10 H.m2/kg

6 3 3 477 X 10- m /mol (Molar) susceptibility Xmo}, K mo] cm /mol, emu/mol (477)2 X 10- l3 H·m2/mol

7 Permeability 1J- dimensionless 477 X 10- H/m, Wb/(A·m)

Relative permeability j 1J-r not defined dimensionless

(Volume) density, W erg/cm3 10- l J/m3 energy product k Demagnetization factor D,N dimensionless 1/477 dimensionless a. and cgs emu are the same for magnetic properties. The defining relation is B =H+477M. b. Multiply a number in Gaussian units by C to convert it to SI (e.g., 1 G X 10-4 T/G = 10-4 T). c. SI (Systeme International d'Unites) has been adopted by the National Bureau of Standards. Where two conversion factors are given, the upper one is recognized under, or consistent with, SI and is based on the definition B = 1J-o(H +M), where 1J-o = 477 X 10-7 H/m. The lower one is not recognized under SI and is based on the definition B =1J-oll +J, where the symbol I is often used in place of J. d. 1gauss = 105 gamma (1'). e. Both oersted and gauss are expressed as em-1I2.g1l2.S-1 in terms of base units. /. A/m was often expressed as "ampere-turn per meter" when used for strength. g. Magnetic moment per unit volume. h. The designation "emu" is not a unit. i. Recognized under SI, even though based on the definition B = 1J-oll +J. See footnote c. j. 1J-r = 1J-/1J-o = 1+X, all in SI. 1J-r is equal to Gaussian 1J-. 3 3 k. B·H and 1J-oM·H have SI units J/m ; M·H and B·H/477 have Gaussian units erg/cm .

R. B. Goldfarb and F. R. Fickett, U.S. De~artment of Commerce, National Bureau of Standards, Boulder, Colorado 80303, March 1985 NBS Special Publication 696 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402