Well as radially magnetized magnets can be really handy in certain experiments I have received a very simple method to make them. Unlike conventional methods which require lots of pain and agony this method is so simple it's hilarious.
Below you can see the simple concept. All you have to use is concentric current loops or a Tesla bifialir coil.
http://upload.wikimedia.org/wikipedia/en/4/47/TeslaBifilar.png
The reason why I said 2d monopole. Is because if you consider the plane that's parallel with the field in the center it will look like a magnetic monopole.
Well not really monopole at all, but as long as you only look
at one side of the coil that will show a radial magnetic field, yes.
The other side of the coil will have an exactly oppositely oriented
magnetic field, and the coil does always make both sides of the
field, so still very much a dipole.
If you're making radially magnetised magnets, then using another such coil
on the other side of your button or ring magnet-to-be, either with the coil
flipped over or the current direction reversed, you should get a stronger
radial magnetic field. Perhaps that helps to create stronger or more evenly
magnetised magnets?
Also, what do you use to make the magnets?
Do you use "soft" iron or nickel? Do you heat them up till red hot before
powering up the magnetising coil? Or do you whack them with a hammer
while the coils are powered up?
Also, does the radial magnetisation in combination with the relatively low
demagnetisation threshold of iron not cause the magnets to lose their
radial magnetisation fairly quickly when you actually use them in a motor
or generator?
kind regards,
Koen
Yes two coils on both sides will work much better in concentrating the field in the middle. And using ferrite was just an example. One can use the best material suited for the job. If you're constantly opposing the field then yes they might demagnetize over time. But that depends on the application you're using them in. For instance If you're using this as a frictionless bearing having one inside the other repelling each it might have an impact on it. But this should be experimented with, Because at the same time this might be completely not true. I believe when they are both equally strong no demagnetization will arise.