Paramagnetic Behavior of Metallic Cerium and Europium

The magnetic behavior of metallic polycrystalline cerium and europium has been studied above room temperatures. The measured paramagnetic behavior of cerium can be explained using the interacting ${\mathrm{Ce}}^{+++}$ ion model ($\theta =-50\mathrm{}°$K) and the Van Vleck theory of paramagnetism with an additional temperature-independent paramagnetic term ${\chi }_c=1.00\mathrm{}\times {10}^{-6\mathrm{}}$ ${\mathrm{g}}^{-1\mathrm{}}$ ${\mathrm{cm}}^3$ resulting from the conduction electrons. Europium metal has an unusual magnetic behavior. Its paramagnetic properties in the solid state cannot be explained on the basis of the noninteracting ${\mathrm{Eu}}^{++}$ model. Near the melting point metallic europium behaves as a collection of weakly interacting ${\mathrm{Eu}}^{+}$ ions. The Bohr magneton number of liquid europium is very close to that of ${\mathrm{Eu}}^{++}$ ions.