ryanuser said:
Ferrofluid does not retain its magnetic effect. It is affected only when a magnet is close to it, I meant is there a sort of fluid that is permanent magnet not temporary. But thanks for the reply
You can make your own ferrofluid (note the name...
ferrofluid... because it's ferromagnetic). Buy some 25 nanometer iron particles (from Sigma Aldrich or similar), mix them in with a clear viscous oil, and you've got your ferrofluid. You'll have to experiment with oil viscosity and amount of iron particles to get the ferrofluid you want.
One interesting application of ferrofluid is a ferrocell:
1) Take two thick pieces of glass or Lexan or similar.
2) Roll a very thin film of ferrofluid on one side of each of the glass pieces.
3) Compress the two glass pieces together (ferrofluid sides together) firmly and evenly while rotating them to disperse the ferrofluid evenly and squish out any excess.
4) Clean up any ferrofluid that squished out.
5) Seal up the perimeter of the two pieces of stacked glass with silicone caulk.
6) Rig up red, green and blue LEDs around the perimeter of each piece of glass (not at the outside so the light shines through the caulk, on each outer side of the glass.
You'll have to make your blue LEDs slightly brighter than your reds and greens, because the glass tends to attenuate blue light. Aim for as white a composite light as you can get.
7) Turn on the LEDs and place a magnet under the glass pieces while viewing it from the opposite side. You'll be able to actually see the magnetic lines of flux in real-time and 3-D, in color (ie: you'll see the red and blue colors diverge).
8) For an even more magnificent 3-D view, stack three or four glass panes together, with ferrorfluid between each. You'll have to ensure your ferrofluid isn't too dark, and you'll double or triple the number of LEDs used, but it's a mind-blowing look at the inner workings of magnets.
You can also use nanometer ferric borate (FeBO3) crystals (they're transparent) and an oil with a slight color to it (or different colors (RGB) for each layer of a multi-layer ferrocell). The nanometer ferric borate is harder to find, though. But it does away with the brown color of traditional ferrofluid.