Very low friction rotator for use at low temperatures and high magnetic fields

We report the development of a sample rotating stage for use in a dilution refrigerator. The rotator makes use of bearings made from commercially avai lable sapphire vee jewels and matching pivots that have extremely low coeff icients of friction. This rotator allows continuous rotations through 360 d egrees at low temperatures (30 mK) and high magnetic fields (20 T) with neg ligible sample heating. Rotations at rates less than 0.33 deg/s resulted in less than 50 mu W of dissipated power. Rotations at rates of 4.4 deg/s res ulted in 383 mu W of heat dissipated. In addition, the rotator is capable o f making rotations with a resolution as small as 0.020 degrees. (C) 1999 Am erican Institute of Physics. [S0034-6748(99)03101-9].