IONIZATION-ENERGY LEVELS OF DIVALENT-CATIONS AND TRANSITION-METAL CATIONS IN Y3FE5O12 SINGLE-CRYSTALS

Correlation between transparency and electrical resistivity for Y3Fe5O 12 Single crystals doped with various diva lent and transition metal c ations is examined. Regardless of the dopant, when the electrical resi stivity becomes greater than 10(5) Omega.cm the transparency at 1.5 mu m drastically increases. The activation energy for various dopants is determined from the temperature dependence of the electrical resistiv ity. The activation energy differs for each dopant, and the value give s the ionization level for carriers in the forbidden band gap.