What is Magnet: Definition and 907 Discussions

A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, cobalt, etc. and attracts or repels other magnets.
A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include the elements iron, nickel and cobalt and their alloys, some alloys of rare-earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a magnetic field, by one of several other types of magnetism.
Ferromagnetic materials can be divided into magnetically "soft" materials like annealed iron, which can be magnetized but do not tend to stay magnetized, and magnetically "hard" materials, which do. Permanent magnets are made from "hard" ferromagnetic materials such as alnico and ferrite that are subjected to special processing in a strong magnetic field during manufacture to align their internal microcrystalline structure, making them very hard to demagnetize. To demagnetize a saturated magnet, a certain magnetic field must be applied, and this threshold depends on coercivity of the respective material. "Hard" materials have high coercivity, whereas "soft" materials have low coercivity. The overall strength of a magnet is measured by its magnetic moment or, alternatively, the total magnetic flux it produces. The local strength of magnetism in a material is measured by its magnetization.
An electromagnet is made from a coil of wire that acts as a magnet when an electric current passes through it but stops being a magnet when the current stops. Often, the coil is wrapped around a core of "soft" ferromagnetic material such as mild steel, which greatly enhances the magnetic field produced by the coil.

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  1. S

    Possible to modify a magnet to be more beamlike

    Possible to modify a magnet to be more "beamlike" I've been wondering if it is possible to encase a magnet in something readily available that would give it more beam-like characteristics vs. field. Basically, I want to have the magnet encased so that I would get full magnetic pull on an...
  2. N

    Question about Magnet: Is it Stationary?

    Hi, I am new to this forum, and I just want to say hi and I am glad that I am here. Now, I have one http://img235.imageshack.us/img235/3324/testra5.gif Isn't the magnet always staying stationary, in one position? Thank you very much. Best regards.
  3. S

    Why are the poles of a magnet stronger?

    Are the force around the poles compressed, so it makes the poles of the magnet stronger than the other parts? Thanks.
  4. M

    Magnetic Flux (Induction - Magnet through a coil)

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  5. M

    What exactly is it that determines that a magnet has only 2 poles?

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  6. malawi_glenn

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  7. P

    Top Quality Magnet Wire: Belden & Beyond

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  8. M

    Magnetization of Permanent Spherical Magnet

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  9. O

    Back E.M.F. & Torque Output of a Permanent Magnet DC Motor

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  10. P

    How Does Storing Magnets North to South Affect Their Longevity?

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  11. S

    Why the direction of the current is determined by which way you move the magnet

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  12. O

    Where Are the Poles of a Flat Refrigerator Magnet?

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  13. A

    Should the poles at the end of each magnet be similar?

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  14. O

    Behavior of a cylindrical magnet

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  15. S

    What make the magnet to be magnet with magnetic field?

    Answer please. Thank you very much. I am talking about permanent magnet.
  16. R

    Can an exterior magnetic field be created using permanent magnet induction?

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  17. R

    Ring Magnets vs. Disk Magnets: Which Creates Stronger Eddy Currents?

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  18. S

    Why there must be time-varying magnet to induce current into conductor?

    Answer please. Thank you.
  19. S

    Can u rust a magnet using vinegar and salt water in a reasonable time?

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  20. R

    The Physics of Dropping a Magnet Through a Copper Tube

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  21. Z

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  22. N

    Identifying Magnetic Rods: Brain-Teaser Challenge

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  23. B

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  24. M

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  25. J

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  26. jal

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  27. D

    How is this magnet too strong?

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  28. P

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  29. C

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  30. C

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  31. K

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  32. B

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  33. R

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  34. L

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  35. D

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  36. N

    Rotate Bar Magnet: Magnetic Field Effects

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  37. T

    Does a Magnet Wear Out? Exploring the Lifespan of Refrigerator Magnets

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  38. R

    Magnet Force: Calculate Force from 1T Magnet & Iron

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  39. B

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  40. A

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  41. M

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  42. O

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  43. V

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  44. C

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  45. K

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  46. C

    Exploring the Effects of a Super-Strength Magnet in Space

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  47. D

    Are Protons Magnets? Investigating Spin & Charge

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  48. A

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  49. Amith2006

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  50. X

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