Sub-10 mK “in-cell” magnetic refrigeration for cryogen-free cryostats

A design and implementation of "in-cell" magnetic refrigeration to achieve sub-10 mK temperatures T in cryogen-free dilution refrigerators is presented. The ultra-low temperatures below 5 mK are attained in finite magnetic fields B up to 1 T. The holding time below 5 mK varies between about 3 and 30 h, depending on the final magnetic field after the demagnetization process. The developed technique can be used to study low dimensional devices at ultra-low electron temperatures in the high B/T regime.