Magneto‐optical properties of RbMnF 3 in the paramagnetic state

The spectrum of the Faraday effect (FE) in the range of 9000 to 37000 cm −1 and its temperature dependence in the range of 90 to 570 K are investigated in RbMnF 3 . The absorption spectrum in the range of 19000 to 60000 cm −1 and the magnetic circular dichroism spectrum in the range of 19000 to 36000 cm −1 are also obtained at room temperature. FE is decomposed to the following components: A 0 , the frequency‐independent FE, A , the diamagnetic FE, and C , the temperature‐dependent paramagnetic FE which are found to be commensurate in value with each other. It is shown that: 1. the paramagnetic magneto‐optical activity for the majority of d—d transitions in RbMnF 3 is close to the maximum possible one in spite of the lack of orbital moment in the ground state of the Mn 2+ ion and due to the spin—orbit interaction in the excited states; 2. C , the term of FE is caused by the highest frequency d—d transition 6 A 1g → 4 T 2g ( 4 F) at ω = 51000 cm −1 ; 3. the diamagnetic FE is caused by the wide band of strong absorption at ω > 60000 cm −1 .