Method for cooling nanostructures to microkelvin temperatures

We propose a new scheme aimed at cooling nanostructures to microkelvin temperature based on the well established technique of adiabatic nuclear demagnetization: we attach each device measurement lead to an individual nuclear refrigerator, allowing efficient thermal contact to a microkelvin bath. On a prototype consisting of a parallel network of nuclear refrigerators, temperatures of similar to 1 mK simultaneously on ten measurement leads have been reached upon demagnetization, thus completing the first steps toward ultracold nanostructures. (C) 2010 American Institute of Physics. [doi:10.1063/1.3489892]