CHROMIUM-EUROPIUM PAIR EMISSION IN EUALO3-CR3+

A detailed discussion of the emission spectrum of trivalent chromium-europium pairs is given. Emission originating on the chromium Eg2 level and terminating on the FJ7 levels of neighboring europium ions has been observed for J=1 through 6. Good agreement is obtained with the D05 to FJ7 emission of pure EuAlO3. The relative intensities of the lines enable us to identify the exchange interaction as the most probable coupling mechanism. Because of the directional character of the chromium-europium exchange, a matrix element of the chromium-ion electron spin exists between the A2g4 and Eg3 even in the absence of spin-orbit interaction. Additional contributions which do not depend on the anisotropy of the chromium orbitals occur when the spin-orbit interaction is included. © 1969 The American Physical Society.