Faraday Effect in Cerium Phosphate Glasses at Low Temperatures

The Faraday effect in glass specimens containing cerium metaphosphate in various concentrations has been measured at 4.2°K and 1.8°K, using 5461 A light, in magnetic fields ranging to 70 kilogauss. The curves of rotation vs $\frac{H}{T}$ were fitted to the Brillouin function for $J=\frac{1}{2}$, yielding values of $g=1.75\mathrm{}$ and $\beta =0.874\mathrm{}$ Bohr magneton. The observed rotations were quite large; for the glass containing the highest concentration of cerium, the rotation approached a saturation value of $4.76\pi$ radians/mm.