Magnetoelectric and second-harmonic spectra in antiferromagneticCr2O3

Abstract

We present a microscopic model to understand the magnetoelectric and second-harmonic spectra of Cr 2 O 3 and the interference effect between the magnetic ( m ) and electric ( e ) second-order optical polarizations. The spin-orbit interaction and the crystalline fields of correct symmetry around the Cr 3ϩ ion, i.e., the axial and twisted crystalline field of C 3 symmetry, are treated as perturbation on the trigonal states of the d 3 system of Cr 3ϩ . By these treatments we attempt to describe the observed phenomena associated with the transitions between 4 A 2g and 4 T 2g states in Cr 2 O 3 . It is possible to reproduce the observed spectra of the polarization rotation and ellipticity, and the second-harmonic generation spectra described by the nonlinear susceptibilities m and e . The estimated theoretical magnitudes of these quantities are in reasonable agreement with the observed magnitudes.

Strong blue emission from Ti-doped crystals

“…Sapphire crystals doped with transition metal such as Ti : Al 2 O 3 and Cr : Al 2 O 3 are famous laser materials, while magneto-electric characteristics and second harmonic spectra of Cr 2 O 3 with the same corundum structure as Al 2 O 3 have been studied experimentally and theoretically. The optical responses of both these doped and pure crystals have been successfully analyzed by the localized model of electronic excitation between multiplets of (3d)-electrons in the transition metal [1,2]. Hereafter, we call it d-d transition.…”

Luminescence channels of manganese-doped spinel

“…The optical responses of both these doped and pure crystals have been successfully analyzed by the localized model of electronic excitation between 3d-orbitals of the transition metal [1,2]. Hereafter we call them d-d transitions.…”

Optical Nonreciprocity in Magnetic Structures Related to High-TcSuperconductors

“…Experiments showed that the rotation is reasonably large and readily observable, of order 10 −4 , illustrating the well-known fact that symmetry arguments are quite powerful in predicting the existence of exotic effects, but not necessarily their magnitude. More recently, microscopic theories that include spin-orbit coupling have brought theory and experiment into agreement [20][21][22].…”