Answer to Question #88754 in Molecular Physics | Thermodynamics for Shivam Nishad

Question

Draw a labelled diagram for the
experimental arrangement used in adiabatic
demagnetization of a paramagnetic
substance. State the lowest temperature
attainable with this method.

Answer 1

Adiabatic demagnetization cooling is an approach to reach very low temperatures. The setup of the device that is used c

an schematically be demonstrated of fig.

Initially (when the system is relatively hot, around 10 K ) the magnetic field of around ~ 10 T is induced in a copper block with a superconducting magnet. The magnetic moments of copper then align along the field, occupying the low energy states. This results in some amount of thermal energy being disposed through the heat switch (basically a pin connecting the mixing chamber and a copper block) away from the cooper block.

Then the system is cooled down to 0.1~0.01 K depending on the delusion refrigerator used and the heat switch is removed.

Magnetic field is then dropped to ~ around 100mT while the copper block cools down due to the released magnetic moments adiabatic (because there is no heat contact between it and other medium ).

The lowest temperature reached in such a setup (cooper) around 10 microK