# Does a magnet's field become stronger or weaker in a vacuum?

This article seems to indicate that a magnet (atleast magnetite, it may not apply to rare earth magnets) weakens when subjected to extremes of pressure. This is purportedly the result of a decrease in electron spacing ... or so I understand from the article.

Does then a magnet's influence change in a vacuum? Does the magnet appear to become stronger in a vacuum? Or is the converse true again?

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Why the tag 'electromagnetism'? –  Everyone Nov 18 '12 at 9:31
One thing to keep in mind is the huge range of pressure scales involved. Their experiments are at about $100,000\textrm{ atm}\approx 10^{10}\textrm{ Pa}$. Normal atomospheric pressure is $1\textrm{ atm}\approx 10^{5}\textrm{ Pa}$, and while we can't really make a strict vacuum in a lab, we can make Ultra-high vacuum, at pressures of $10^{-7}\textrm{ Pa}$. While John Rennie is most probably correct, one must always be wary when describing phenomena ranging over 17 orders of magnitude. –  Emilio Pisanty Nov 18 '12 at 12:30