Electronic and Nuclear Magnetism in Platinum-Iron at Ultralow Temperatures

Abstract

In February 1996, physicists at the University of Bayreuth claimed a world record for producing the lowest temperature yet achieved when they announced the results of their work with platinum. They cooled 31.4 grams of platinum to 2 millionths of a degree Celsius above absolute zero temperature, -273.15°C. In this paper they describe the theory and the practical work behind this accomplishment. Research in low temperature physics involves the construction of detailed and precise knowledge of the atomic and nuclear structures and their interactions in atoms. Some effects due to atomic and nuclear structure, particularly magnetic effects, are only seen at very low temperatures; however their effects have consequences at higher temperatures, although these are not usually observed. Thus, this and other low temperature work is contributing to a fundamental understanding of the magnetic behaviour of materials.