Re: Magnetism: compare magnetic fields

"Sam Wormley" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> sci wrote:
> >
> > Looking for a direct mathmatical comparison between the magnetic field
> > produced by an electronic current (i) and that of a fixed magnet of a
> > given strength.
>
> See: http://scienceworld.wolfram.com/physics/Magnetism.html
>   Note the differences in
>   o diamagnetism
>   o ferromagnetism <===
>   o Paramagnetism
>
> Ferromagnetism
>   http://scienceworld.wolfram.com/physics/Ferromagnetism.html
>
>   "The development of extremely strong magnetic properties in certain
>   materials which occurs when magnetic domains (regions at most 1 mm in
>   dimension) become aligned in the absence of an applied field, below a
>   temperature known as the Curie temperature. The net magnetization
>   depends on the magnetic history (the hysteresis effect). Above the
>   Curie temperature, these materials become paramagnetic. Iron, nickel,
>   cobalt, and gadolinium are ferromagnetic at room temperature.
>   Ferromagnetism is believed to be caused by magnetic fields generated
>   by the electrons' spins in combination with a mechanism known as
>   exchange coupling, which aligns all the spins in each magnetic
>   domain".