Phase Diagram of Liquid<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">He</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>3</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>between 0.7 and 2.5 mK

Abstract

We describe a nuclear demagnetization cryostat in which liquid $^{3}\mathrm{He}$ has been cooled to below 0.7 mK. Data on the boundaries between the normal Fermi-liquid and the superfluid phases of $^{3}\mathrm{He}$, as determined from NMR measurements, are presented between 0.7 and 2.5 mK and from 0 to 27 bar. The "$\ensuremath{\lambda}$ point" of $^{3}\mathrm{He}$ was found at 0.93 mK.