Influence of Light on Paramagnetic Susceptibility

Abstract

THE so-called ‘photomagnetic effect’ was first described by Bose and Raha¹ as a decrease in the paramagnetic susceptibility of chromic chloride and of several other salts on exposure to light. Later the same authors corrected themselves² and claimed an increase in susceptibility followed by a slow decrease. Specchia^3,4 and Gorter⁵ have also investigated the effect, the former finding a slight increase followed by a slow decrease, while the latter found only the decrease. None of these workers states the sensitivity of the apparatus used, although Specchia, who used the capillary rise method, says that water gave a deflection of 3,000 scale divisions.