What are the applications of Quadrupole Neodymium magnets?

[boeland]

There are lots of patents on Neo magnets and they are difficult to sort out. Some of the patents restrict the use of the magnets that contain cobalt and/or have a tetragonal crystalline structure.
Does someone know:

What types of magnets contain cobalt?
What types of magnets have a tetragonal structure?

 

[Gokul43201]

Most NdFeB magnet patents are held by GE and/or Sumitomo. You should check with them.

I expect there's a lot of literature on Co doping in the Fe site (I think it increases Tc and uniaxial anisotropy, up to some optimal doping), but know absolutely nothing about patents here.

 

[boeland]

The Neomax (Sumitomo) and Magnequench (GM) patents do require licences for Neo magnets that contain cobalt and have tetragonal structures. I am curious if all high energy (>30MOe) and high temperature (>110C) magnets use this type of technology.

 

[Nerble]

Does anyone know who has the patents on Quadrupole Neodymium. I found a video of one on YouTube:

You can find these magnets in particle accelerators, and they have 4 poles (Quadrupole). This one is a permanent magnet, and without the video I couldn't tell the difference between it and an ordinary bar magnet.