Magnetic Dipole Moment
A vector quantity determining the torque experienced by a magnetic dipole when placed in an external magnetic field.
Governing formula
μ = I A, U = -μ · B
SI unit
A·m² (or J/T)
In depth
In an external magnetic field B, torque τ = μ × B rotates the dipole until its magnetic moment aligns parallel with field B.
Examples in the real world
The intrinsic electron spin magnetic moment (μ_e ≈ 9.28 × 10⁻²⁴ J/T) responsible for ferromagnetism in transition metals.