Re: What would the gauss measurement be for magnets made of neodymium material?

Neodymium is a rare-earth metal that can be used to make permanent magnets. The "remanence" of a permanent magnet is the size of the magnetic field, or the "gauss measurement" as you call it, that remains when external fields are turned off.

The exact remanence of any permanent magnet depends very strongly on the composition and the history of the material. The production method, the temperature and magnetic field applied during production, and the cooling rate, all affect the final permanent field, or remanence.

I looked at a couple of references and some vendor Web sites. Commercially available neodymium-based magnets are NdFeB (Neodymium-Iron- Boron). Their remanence is generally in the range of 10,500-14,000 Gauss. For comparison, SmCo (Samarium-Cobalt) runs in the 8,000-12,000 Gauss range, Ferrite (the most widely used material) is 2,000-4,000 Gauss, and Alnico (Aluminum-Nickel-Cobalt) comes in a huge variety of alloys that span 6,000-13,500 Gauss. The earth's magnetic field is about 0.1 Gauss at the surface.

Although Alnico and SmCo can compete with NdFeB for remanence, the most common use for such materials is to shape and enhance magnetic fields applied by electromagnets. In that situation, these materials eventually saturate when the applied field is too high. In such high-energy appications, NdFeB is the material of choice because it can retain its magnetic properties at much higher fields than the others. It's roughly 50% better than SmCo, 5 times better than Alnico, and 10 times better than Ferrite. There's a nice side-by-side comparison complete with graphs on the Dexter Magnetic Materials web site.