Temperature Scale for Neodymium Ethylsulfate Below 1 °K

A thermodynamic method, γ-ray heating a statistical-mechanical method, and nuclear orientation, were used in a complementary fashion to determine the final temperature reached on demagnetizing a single crystal of neodymium ethylsulfate (NES) from magnetic fields up to 20 kG, applied along the c axis at 1 ^∘{}K. The temperature scale so established allows nuclear-orientation data to be fitted much more satisfactorily than did the old scale, removing a troublesome S-shaped deviation. Two independent checks were made of the validity of the new scale. The nuclear magnetic moment of Ce¹³⁷ᵐ is again corrected. The best value, obtained from orientation in both NES and cerium magnesium nitrate lattices is 0.69±{}0.03 nm, using 〈r^-3〉4f=4.44 atomic units.