Observation of Ferromagnetic Ordering in hcp3He

High-density bcc and hcp ${}^3$He have been cooled into the magnetically ordered state by direct nuclear demagnetization. Pressure changes during precooling and demagnetization indicated the magnetic state of the system. For a bcc sample with $v=20.10\mathrm{}{\mathrm{cm}}^3/\mathrm{mole}$, the two well-known magnetic transitions were observed. For hcp samples precooled to $614\mu \mathrm{K}$ in a field of 2.5 T, for which the spin entropy is almost zero, the transition to the ferromagnetic state was indicated by a decrease in pressure near the end of the demagnetization. For hcp samples with $S\ge 0.46R\ln 2$ ferromagnetic ordering did not occur.