THE PRODUCTION OF TEMPERATURES BELOW 1 DEGREE K BY THE ADIABATIC DEMAGNETIZATION OF 50% CE(PO3)3-BA(PO3)2 GLASS.
Abstract
It was the object of the investigation to determine whether cerium metaphosphate glass (specifically 50% by weight Ce(PO3)3-Ba(PO3)2) is a suitable coolant material for adiabatic demagnetization experiments. Cerium glass is not susceptible to dehydration and attack by glycerine (used for thermal contact) as are many of the hydrated salts. In addition, the concentration of magnetic atoms can be varied over a wide range by diluting the magnetic glass Ce(PO3)3 with the nonmagnetic glass Ba(PO3)2. The principal results of this investigation are: (a) the 50% Ce(PO3)3-Ba(PO3)2 glass was successfully cooled many times by adiabatic demagnetization, and 'magnetic' temperatures as low as 0.0069K were reached, (b) using a cerium magnesium nitrate paramagnetic salt as a thermometer, absolute temperatures as low as 0.02K were observed, and (c) within experimental error, the measured Curie constant for the cerium glass (density 3.57) agrees with that calculated from the Brillouin function for J = 1/2 and 1.97 < or = g < or = 2.00. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 15, 1968
- Accession Number
- AD0673525
Entities
People
- Edwin Lewis Althouse
Organizations
- United States Naval Research Laboratory