Magnetooptics of Pr3+ Ions in Trigonal Ca-Gallogermanate Magnetooptics of Pr3+ Ions in Trigonal Ca-Gallogermanate Ca3Ga2Ge4O14

Abstract

Experimental investigation of magnetic circular dichroism (MCD) at the temperatures 90K and 300Kwas carried out in the visible region in disordered trigonal Ca-gallogermanates Сa3Ga2Ge4O14 doped with small concentration (ï¾5 at.%) of Pr3+ rare-earth (RE) ions. The spectral dependences of MCD (magnetic dichroism) spectra were measured within 400-500 nm. It was found that the squares of MCD bands increased in magnitude with decreasing temperature. The MCD bands belong to the forbidden (in parity) 4f4f transitions 3Ð4→3P2 (λ = 450 nm) and 3Ð4→3P1 (λ = 475 nm) and the results undoubtedly indicated the existence of the so-called "paramagnetic" contribution (C-term of MCD in Сa3Ga2Ge4:Pr3+. From the spectral dependence of MCD in the 3Ð4→3P2 transition we conclude that the so-called “diamagnetic†contribution (A-term) to MCD is not so small. We have determined the “paramagnetic†constants С for the transitions to the 3P2 and 3P1 multiplets in accordance to the formula of the temperature dependence of zero moment (or square) of MCD bands at λ = 450nm and 475 nm.