PRESSURE MEASUREMENT DURING NUCLEAR DEMAGNETIZATION OF BCC AND HCP SOLID HE-3

Direct nuclear demagnetization is used to cool high density solid He-3 into the magnetically ordered phases. The pressure change in the samp les is detected by a capacitive strain gauge. The entropy of the sampl es is removed by precooling to a temperature of 0.5 mK in a field of 2 .5 T. For a bcc sample with a molar volume of 20.10 cm(3)/mol, two mag netic transitions have been observed. A similar experiment on an hcp s ample with a molar volume of 19.65 cm(3)/mol is being done. Preliminar y data indicates no abrupt change in the pressure as observed in the b ce sample.