7.7 Method of Adiabatic Demagnetization
A sketch of the apparatus used for adiabatic demagnetization is shown in Fig. 7.8. The substance S a paramagnetic salt of Gd2(SO4)8 H2O or FeNH4,(SO4)12 H2O is pressed into a sphere or ellipsoid. It is coated with a thin layer of stop-cock grease to prevent oxidation or dehydration. It is suspended by silk thread at the centre of the secondary coils which is used for measurement of susceptibility inside a calorimeter immersed in boiling helium at a temperature of about 1 K. This in turn is surrounded by a bath of liquid nitrogen. The whole system is placed between the pole pieces of electromagnet. To perform the experiment, the calorimeter is filled with helium at a pressure of 1 mm of Hg.
Fig. 7.8 ...
Get Heat and Thermodynamics now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
