Pyrochlore magnet shows consistent strength and practically no thermal expansion over temperature range of over 400 Kelvins

https://www.eurekalert.org/news-releases/1072410

"zirconium, niobium, iron, cobalt alloy even better thermal non-expansion properties than that of iron, nickel... only changes  around one ten-thousandth of 1% per Kelvin... certain electrons change state as temperature rises, causing magnetic order to decrease, and contraction, almost exactly canceling expansion... pyrochlore magnet does not have perfect lattice structure repeating exactly same way: some areas contain more cobalt, some less, near-zeroing overall expansion... aviation, aerospace, high-precision electronics"