The application or removal of a magnetic field of order 5 T to some Gd compounds at low temperatures results in 10–20 K adiabatic temperature changes or the isothermal expulsion or absorption of heat. In particular, the heat absorbed by 1 liter of appropriate magnetic material at 2 K is several hundred J. A rotating device is decribed which will allow cycle times of much less than 1 sec, resulting in approximately 1‐kW refrigeration capacity for each liter of paramagnetic Gd compound. This heat could be expelled with better than 80&percent; of Carnot efficiency into a helium refrigerator operating at 10–14 K.