Magnetic Moment

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The magnetic moment is a defined quantity describing the strength of the magnet produced by current flowing through a loop of conductor:

μ = current*area_of_loop = IA

since current is given in amperes and area in square meters the units of magnetic moment are amp*m2.

The loop is thus creating a magnet whose strength is assigned the value current*loop area.


Unfortunately, as in many fields these units are altered and renamed based on the application. This just causes confusion so the practice should be abolished, but until wiser heads prevail, here are some of the alternate units that magnetic moments are often expressed in:

  • joule/Tesla -used commonly in the physics literature (kgm2/s2)/(kg/amp*s2)=amp*m2

Since current is related to the electric charge the magnetic moment can be related to charges as well.

There are other definitions for magnetic moment, but the units end up being amp*m2 so it is probably best to think of this definition when using magnetic moments.

Elementary particles have intrinsic magnetic moments which have to be measured:

Particle Magnetic dipole moment

(10−27 J⋅T−1)

electron (e-) −9284.764
proton (H+) 14.106067
neutron (n) −9.66236

Since nuclear magnetic moments are smaller than electron magnetic moments, and the magnetic moment is a number representing the strength of a magnet, the electrons in a molecule determine the magnetic properties of a material, not the nuclei.