Abstract
Just as electrons engage in spontaneous magnetic ordering, accounting for such phenomena as ferromagnetic domains, so too can nuclei order spontaneously. However, because nuclear magnetic moments are very much smaller than electron magnetic moments, spontaneous nuclear ordering occurs only at extremely low temperatures. As we will see, experiments conducted in the course of research on nuclear ordering have produced spin temperatures as low as 25 nanokelvins in copper and 2 nanokelvins in silver.