The Role of 4f–4f Transitions in Magnetooptics of Paramagnetic Rare–Earth Glasses

Abstract

Theoretical and experimental investigations are made of magnetooptical activity (MOA) of (parity) forbidden intraconfigurational4f-4f transitions in Er(PO,), rare-earth paramagnetic phosphate glasses. The interpretation of magnetooptical spectra in frames of a theoretical scheme similar to Judd-Offelt's theory is carried out for the observed 4f-4f transitions. It is shown that the theory may be used successfully for the quantitative description of magnetic circular dichroism (MCD) spectra (and Faraday effect spectra) in rare-earth paramagnetic glasses.

Czochralski Growth, Magnetic Properties and Faraday Characteristics of CeAlO3 Crystals

“…Faraday magneto-optical effect of rare earth ions is mainly caused by the transitions of 4f-4f5d [36,37], which is essentially the circular birefringence induced by the applied magnetic field. MCD signal of the rare earth magnetic ions at the transition absorption can be indicative of their magneto-optical activity (MOA) [38]. Usually the shorter the transition absorption wavelength and the stronger the intensity, the stronger the corresponding MCD signal.…”

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

“…For instance, in Refs. [4][5][6], a theoretical scheme similar to that of the Judd-Ofelttheory [1][2] was used to interpret the magnetooptical spectra caused by the forbidden 4f → 4f transitions. This scheme contains several phenomenological parameters F(usually there are three, i.e., = 2, 4, 6, but in some cases there may be fewer) depending on the asymmetrical electrostatic field of the RE-ion environment in the media (crystal, paramagnetic glasses, and solutions).…”

“…This scheme contains several phenomenological parameters F(usually there are three, i.e., = 2, 4, 6, but in some cases there may be fewer) depending on the asymmetrical electrostatic field of the RE-ion environment in the media (crystal, paramagnetic glasses, and solutions). According to [4][5][6] the corresponding expression for the MCD "paramagnetic" contribution (i.e., C-term of MCD) can be written as:…”

“…is the 6j-symbol [5,6]; 0 g is the Lande factor of the ground 0 0 0 J S L multiplet RE-ion under consideration.  F parameters can be determined from the magnetooptical experiment and are common for all electronic transitions within the RE-ion 4fn ground configuration.…”

“…Let us now consider this theoretical scheme in more detail; the interpretation of the magnetic circular dichroism (MCD) spectra [4] are caused by the parity-forbidden intra-configurational 4f→4f transitions in the specific case of disordered RE-compounds (solutions, paramagnetic glasses etc.). Then according to [5,6], the main factor determining the features of an energy spectrum and wave functions of the RE-ions in disordered media are the fluctuations of the local parameters of both the even and odd crystal fields. Indeed, supposing that the CF parameter fluctuations are independent, and performing the statistical averaging of the odd CF coefficient combinations over all possible orientations of RE-centers in disordered media, we can obtain the following useful expression [5,6]:…”