Oxygen Loses Magnetism at High Pressures

But why would you want to do this?

At one point in the process there is an area between being magnetic and being a superconductor, there is a spot where solid oxygen is not magnetic. If you know where that boundary is you can more easily toggle between those two states.

If you happen to find yourself at 80,000 atm.

Whoa! Since when is oxygen magnetic?

Ok, technically it's not magnetic its paramagnetic. I means that liquid oxygen can be manipulated by a magnetic field without having a field of its own.
Here is a few theories about why this happens.

Why would anyone WANT to put that kind of pressure on ANYTHING? I'd like to see the machinery that is capable of that.

This seems to fall into the category of "because they can" - they wanted to find the actual point in what had previously been an understood range. I agree though, whatever pump system they are using to achieve 80,000 ATM would be awesome to see in action.

From the sound of things they used 2 small anvils. It is a very trace amount and it's more easily able to be compressed.