Adiabatic nuclear demagnetization

COMMENT. Temperatures as low as 3.5 x 10 K have never been achieved. However, a temperature of 2 X IQ- K has been attained by adiabatic nuclear demagnetization (Chapter 3). 

For example in copper, a metal used in nuclear adiabatic demagnetization (see Section 7.4), electron and phonon systems are decoupled the power transferred between the two systems is [18] ... 

G. P. Jones, J. T. Daycock and T. T. Roberts, "A sample moving system for nuclear magnetic resonance adiabatic demagnetization experiments." J. Phys. E Sci. Instrum. 2, 630-631 (1969). 

Roinel et al. (1985) have made a detailed study of the relaxation rates for the enhanced Tm (/ = ) nuclear spins as a function of temperature from 0.05 up to 2 K, in fields up to 4 T perpendicular to the c-axis. The variation of the relaxation rate is rather complex at 50-100 mK recovery is generally non-exponential. At fields below 0.5 T, relaxation is dominated by interactions with electronic impurities, but above 1T effects are attributed to a bottle-neck between phonons and bath. It is concluded that the relaxation rate at low fields would be too short to allow study of a nuclear ordered state, produced by adiabatic demagnetization of the enhanced Tm nuclear spins. 

Based on Andres ideas and results, Pobell and co-workers of the Institut fiir Festkorperforschung, Kernforschunsanlage Jiilich, designed a two-stage nuclear hyperfine adiabatic demagnetization refrigerator, hopefully to set a record for... 

In adiabatic demagnetization experiments, Suzuki et al. (1983) observed antiferromagnetic ordering of the enhanced nuclear spin system of Ho in CsaNaHoCle with the ground nonmagnetic doublet at 1.5 mK. Murao (1988) considered the coupled equations of motion of the electron and nuclear magnetic moments in this crystal with reference... 

---