Magnetic moment Definition and 181 Threads

The magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field. Examples of objects that have magnetic moments include: loops of electric current (such as electromagnets), permanent magnets, elementary particles (such as electrons), various molecules, and many astronomical objects (such as many planets, some moons, stars, etc).
More precisely, the term magnetic moment normally refers to a system's magnetic dipole moment, the component of the magnetic moment that can be represented by an equivalent magnetic dipole: a magnetic north and south pole separated by a very small distance. The magnetic dipole component is sufficient for small enough magnets or for large enough distances. Higher-order terms (such as the magnetic quadrupole moment) may be needed in addition to the dipole moment for extended objects.
The magnetic dipole moment of an object is readily defined in terms of the torque that object experiences in a given magnetic field. The same applied magnetic field creates larger torques on objects with larger magnetic moments. The strength (and direction) of this torque depends not only on the magnitude of the magnetic moment but also on its orientation relative to the direction of the magnetic field. The magnetic moment may be considered, therefore, to be a vector. The direction of the magnetic moment points from the south to north pole of the magnet (inside the magnet).
The magnetic field of a magnetic dipole is proportional to its magnetic dipole moment. The dipole component of an object's magnetic field is symmetric about the direction of its magnetic dipole moment, and decreases as the inverse cube of the distance from the object.

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  1. Suraj M

    Magnetic moment and magnetic properties

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  2. Priyadarshini

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  3. sergiokapone

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  4. H

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  5. Maximtopsecret

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  6. J

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  7. F

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  8. T

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  9. T

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  10. N

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  11. AdityaDev

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  12. ognik

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  13. schrodingerscat11

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  15. D

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  16. V

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  17. Prashasti

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  18. nmbr28albert

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  19. kartikwat

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  20. B

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  21. R

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  22. carllacan

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  23. carllacan

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  24. B

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  25. E

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  26. I

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  27. S

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  28. J

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  29. H

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  30. Z

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  31. M

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  32. Z

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  33. S

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  34. H

    Why the magnetic moment is zero for occupied levels?

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  35. W

    Magnetic moment in a uniform/non-uniform magnetic field?

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  36. I

    Magnetic Moment of Point Charge

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  37. S

    Magnetic Moment of a Charged, Rotating Sphere Problem

    Homework Statement Show for a solid spherical ball of mass m rotating about an axis through its center with a charge q uniformly distributed on the surface of the ball that the magnetic moment μ is related to the angular momentum L by the relation μ=(5q/6mc)L Homework Equations μ=IA/c...
  38. V

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  39. T

    NMR Magnetic Moment: Understanding Bloch Equations and Relaxation Terms

    Let M be the magnetic moment of a system. Below are the Bloch equations, including the relaxation terms. dM_x/dt=({\bf M} \times \gamma {\bf H_0})_x-M_x/T_2 dM_y/dt=({\bf M} \times \gamma {\bf H_0})_y-M_y/T_2 dM_z/dt=({\bf M} \times \gamma {\bf H_0})_z+(M_{\infty}-M_z)/T1 At t=0, {\bf...
  40. C

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    I saw the equation here http://en.wikipedia.org/wiki/Magnetic_moment#Current_loop_definition for the definition of the magnetic moment for a non-planar loop. Can someone tell me if there's a name for this equation m= \frac { I }{ 2 } \int { \overrightarrow { r } } \times d\overrightarrow { r }...
  41. L

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  42. P

    Stupid question on anomalous magnetic moment of the electron

    I don't understand one think: when we calculated the correction of the magnetic moment of the electron, we consider only the finite terms of the vertex correction that non depend on the parameter μ. Using Ryder notation , we consider only \bar{u}(p')(γμ+\Lambdaμ(2))u(p) but there is also...
  43. N

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  44. T

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  45. A

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  46. A

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  47. K

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  48. J

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  49. Q

    A Question about Spin Induced Magnetic Moment

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  50. D

    How do you calculate the Magnetic Moment of a Permanent Magnet?

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