That's kind of what the article is talking about. You can do it in a ferromagnetic material (like in your link) but then you've got the problem that it's a magn

That's kind of what the article is talking about. You can do it in a ferromagnetic material (like in your link) but then you've got the problem that it's a magnet and screwing up everything around it. The idea here is that you can do it in something that is overall neutral.