Thermal and magnetic properties of cerium ethyl sulphate between 0·02 and 1 °K

Abstract

Adiabatic demagnetization experiments have been carried out on a spherical single crystal of cerium ethyl sulphate. The absolute temperature scale was determined down to 0·02 °K as a function of the entropy. Measurements were also made of the adiabatic susceptibility in the antiferromagnetic state which sets in at 0·05 °K and by extrapolation the magnetization at T = 0 °K could be estimated to a fair accuracy. The co-operative phenomena are discussed in terms of the theory of electric quadrupole-quadrupole interaction by Finkelstein.