Measurements of the melting pressure of a sample of containing less than 40-ppm impurities, self-cooled to below 2 mK in a Pomeranchuk compression cell, indicate the existence of a new phase in solid below 2.7 mK of a fundamentally different nature than the anticipated antiferromagnetically ordered state. At lower temperatures, evidence of possibly a further transition is observed. We discuss these pressure measurements and supporting temperature measurements.
- Received 10 February 1972
- Published in the issue dated 3 April 1972
© 1972 The American Physical Society