PROCEDE DE REFRIGERATION MAGNETIQUE

摘要

Magnetic refrigeration uses paramagnetic cpds. in which the entropy reduces markedly at low temps. in the presence of a magnetic field owing to a change in the crystallographic phase of the components. The compounds used pref. are of formula R'xR21-x.X.0.4 where R.1 and R2 are rare earth metals; X is a gp. (V) element and x is between O and 1. Pref. examples are R1 lutetium, R1 thulium and x vanadium or R1 and R2 dysprosium and X vanadium. Pref. x is less than 0.1. Used in physico-industrial low temp. applications such as the use of electronic apparatus at low temps. and the production of the intense magnetic fields of superconducting coils. The paramagnetic compounds used give a great variation of entropy.