Adiabatic Magnetization of a Superconducting Sphere

Measurements are reported of the temperature changes accompanying suppression of the superconductivity of a lead sphere by adiabatic magnetization. Observations were made in the temperature range 2.1°K to 4.3°K for magnetizations into the complete range of the intermediate state. The magnetic fields were applied as step functions of time, and allowance was made for the resulting eddy-current heating. After magnetization, practically complete temperature equilibrium was established in the order of 15 seconds. Temperature changes observed on magnetization were in quantitative agreement with values predicted from calorimetric data and demonstrate a linear relationship between the applied magnetic field and the fraction of normal metal produced in the intermediate state.